def deserialize_keras_object(identifier,
module_objects=None,
custom_objects=None,
printable_module_name='object'):
"""Turns the serialized form of a Keras object back into an actual object."""
if identifier is None:
return None
if isinstance(identifier, dict):
# In this case we are dealing with a Keras config dictionary.
config = identifier
(cls, cls_config) = class_and_config_for_serialized_keras_object(
config, module_objects, custom_objects, printable_module_name)
if hasattr(cls, 'from_config'):
arg_spec = tf_inspect.getfullargspec(cls.from_config)
custom_objects = custom_objects or {}
if 'custom_objects' in arg_spec.args:
return cls.from_config(
cls_config,
custom_objects=dict(
list(_GLOBAL_CUSTOM_OBJECTS.items()) +
list(custom_objects.items())))
with CustomObjectScope(custom_objects):
return cls.from_config(cls_config)
else:
# Then `cls` may be a function returning a class.
# in this case by convention `config` holds
# the kwargs of the function.
custom_objects = custom_objects or {}
with CustomObjectScope(custom_objects):
return cls(**cls_config)
elif isinstance(identifier, six.string_types):
object_name = identifier
if custom_objects and object_name in custom_objects:
obj = custom_objects.get(object_name)
elif object_name in _GLOBAL_CUSTOM_OBJECTS:
obj = _GLOBAL_CUSTOM_OBJECTS[object_name]
else:
obj = module_objects.get(object_name)
if obj is None:
raise ValueError(
'Unknown {}: {}. Please ensure this object is '
'passed to the `custom_objects` argument. See '
'https://www.tensorflow.org/guide/keras/save_and_serialize'
'#registering_the_custom_object for details.'.format(
printable_module_name, object_name))
# Classes passed by name are instantiated with no args, functions are
# returned as-is.
if tf_inspect.isclass(obj):
return obj()
return obj
elif tf_inspect.isfunction(identifier):
# If a function has already been deserialized, return as is.
return identifier
else:
raise ValueError('Could not interpret serialized %s: %s' %
(printable_module_name, identifier))
def get_training_arg_index(call_fn):
"""Returns the index of 'training' in the layer call function arguments.
Args:
call_fn: Call function.
Returns:
- n: index of 'training' in the call function arguments.
- -1: if 'training' is not found in the arguments, but layer.call accepts
variable keyword arguments
- None: if layer doesn't expect a training argument.
"""
argspec = tf_inspect.getfullargspec(call_fn)
if argspec.varargs:
# When there are variable args, training must be a keyword arg.
if 'training' in argspec.kwonlyargs or argspec.varkw:
return -1
return None
else:
# Try to find 'training' in the list of args or kwargs.
arg_list = argspec.args
if tf_inspect.ismethod(call_fn):
arg_list = arg_list[1:]
if 'training' in arg_list:
return arg_list.index('training')
elif 'training' in argspec.kwonlyargs or argspec.varkw:
return -1
return None
def __init__(self, x, y, image_data_generator,
batch_size=32,
shuffle=False,
sample_weight=None,
seed=None,
data_format=None,
save_to_dir=None,
save_prefix='',
save_format='png',
subset=None,
dtype=None):
if data_format is None:
data_format = backend.image_data_format()
kwargs = {}
if 'dtype' in tf_inspect.getfullargspec(
image.NumpyArrayIterator.__init__)[0]:
if dtype is None:
dtype = backend.floatx()
kwargs['dtype'] = dtype
super(NumpyArrayIterator, self).__init__(
x, y, image_data_generator,
batch_size=batch_size,
shuffle=shuffle,
sample_weight=sample_weight,
seed=seed,
data_format=data_format,
save_to_dir=save_to_dir,
save_prefix=save_prefix,
save_format=save_format,
subset=subset,
**kwargs)
def __init__(self, layer):
self.layer = layer
self.layer_call_method = _get_layer_call_method(layer)
self._expects_training_arg = utils.layer_uses_training_bool(layer)
self._training_arg_index = utils.get_training_arg_index(
self.layer_call_method)
# If the layer call function has kwargs, then the traced function cannot
# have an input signature.
arg_spec = tf_inspect.getfullargspec(self.layer_call_method)
self._has_kwargs = bool(self._expects_training_arg or arg_spec.defaults
or arg_spec.kwonlyargs or arg_spec.varkw)
self._input_signature = self._generate_input_signature(layer)
self._functions = weakref.WeakValueDictionary()
# Bool indicating whether this object is currently tracing the layer call
# functions.
self.tracing = False
# Get the input argument name from the args.
args = arg_spec.args
if tf_inspect.ismethod(self.layer_call_method):
args = args[1:]
self._input_arg_name = args[0] if args else 'inputs'
def __init__(self, cell, *args, **kwargs):
super(_RNNCellWrapperV2, self).__init__(*args, **kwargs)
self.cell = cell
cell_call_spec = tf_inspect.getfullargspec(cell.call)
self._expects_training_arg = ("training" in cell_call_spec.args) or (
cell_call_spec.varkw is not None
)
def fn_args(fn):
"""Get argument names for function-like object.
Args:
fn: Function, or function-like object (e.g., result of `functools.partial`).
Returns:
`tuple` of string argument names.
Raises:
ValueError: if partial function has positionally bound arguments
"""
if isinstance(fn, functools.partial):
args = fn_args(fn.func)
args = [a for a in args[len(fn.args):] if a not in (fn.keywords or [])]
else:
if hasattr(fn, '__call__') and tf_inspect.ismethod(fn.__call__):
fn = fn.__call__
args = tf_inspect.getfullargspec(fn).args
if is_bound_method(fn) and args:
# If it's a bound method, it may or may not have a self/cls first
# argument; for example, self could be captured in *args.
# If it does have a positional argument, it is self/cls.
args.pop(0)
return tuple(args)
def has_valid_get_config_method(layer):
all_args = tf_inspect.getfullargspec(layer.__init__).args
expected_args = ('trainable', 'name', 'dtype', 'dynamic', '_batch_input_shape', 'self')
# Finds all arguments in the `__init__` that are not in the config:
extra_args = [arg for arg in all_args if arg not in expected_args]
# Check that either there are no new arguments or that `get_config` has been overridden:
if len(extra_args) > 0 and hasattr(layer.get_config, '_is_default'):
return False
return True
def testTrainingDefaults(self):
def assert_training_default(fn, default_value):
arg_spec = tf_inspect.getfullargspec(fn)
index = len(arg_spec.args) - arg_spec.args.index('training')
self.assertEqual(arg_spec.defaults[-index], default_value)
class LayerWithTrainingRequiredArg(keras.engine.base_layer.Layer):
def call(self, inputs, training):
return control_flow_util.smart_cond(
training, lambda: inputs * 0,
lambda: array_ops.identity(inputs))
class LayerWithTrainingDefaultTrue(keras.engine.base_layer.Layer):
def call(self, inputs, training=True):
return control_flow_util.smart_cond(
training, lambda: inputs * 0,
lambda: array_ops.identity(inputs))
class Model(keras.models.Model):
def __init__(self):
super(Model, self).__init__()
self.layer_with_training_default_none = LayerWithLearningPhase(
)
self.layer_with_training_default_true = LayerWithTrainingDefaultTrue(
)
self.layer_with_required_training_arg = LayerWithTrainingRequiredArg(
)
def call(self, inputs):
x = self.layer_with_training_default_none(inputs)
x += self.layer_with_training_default_true(inputs)
x += self.layer_with_required_training_arg(inputs, False)
return x
model = Model()
# Build and set model inputs
model.predict(np.ones([1, 3]).astype('float32'))
saved_model_dir = self._save_model_dir()
model.save(saved_model_dir, save_format='tf')
load = tf_load.load(saved_model_dir)
# Ensure that the Keras loader is able to load and build the model.
_ = keras_load.load(saved_model_dir)
assert_training_default(load.__call__, False)
assert_training_default(load.layer_with_training_default_none.__call__,
False)
assert_training_default(load.layer_with_training_default_true.__call__,
True)
# Assert that there are no defaults for layer with required training arg
arg_spec = tf_inspect.getfullargspec(
load.layer_with_required_training_arg.__call__)
self.assertFalse(arg_spec.defaults) # defaults is None or empty
def __init__(self,
featurewise_center=False,
samplewise_center=False,
featurewise_std_normalization=False,
samplewise_std_normalization=False,
zca_whitening=False,
zca_epsilon=1e-6,
rotation_range=0,
width_shift_range=0.,
height_shift_range=0.,
brightness_range=None,
shear_range=0.,
zoom_range=0.,
channel_shift_range=0.,
fill_mode='nearest',
cval=0.,
horizontal_flip=False,
vertical_flip=False,
rescale=None,
preprocessing_function=None,
data_format=None,
validation_split=0.0,
dtype=None):
if data_format is None:
data_format = backend.image_data_format()
kwargs = {}
if 'dtype' in tf_inspect.getfullargspec(
image.ImageDataGenerator.__init__)[0]:
if dtype is None:
dtype = backend.floatx()
kwargs['dtype'] = dtype
super(ImageDataGenerator, self).__init__(
featurewise_center=featurewise_center,
samplewise_center=samplewise_center,
featurewise_std_normalization=featurewise_std_normalization,
samplewise_std_normalization=samplewise_std_normalization,
zca_whitening=zca_whitening,
zca_epsilon=zca_epsilon,
rotation_range=rotation_range,
width_shift_range=width_shift_range,
height_shift_range=height_shift_range,
brightness_range=brightness_range,
shear_range=shear_range,
zoom_range=zoom_range,
channel_shift_range=channel_shift_range,
fill_mode=fill_mode,
cval=cval,
horizontal_flip=horizontal_flip,
vertical_flip=vertical_flip,
rescale=rescale,
preprocessing_function=preprocessing_function,
data_format=data_format,
validation_split=validation_split,
**kwargs)
def convert_to_functional(model_subclass, dataset):
"""
Convert original subclass model to a functional one. We pass the flag `training=None` for subclass models whose
layers pass the `training` flag to other layers explicitly, so if their default value was `training=False` this will
be overwritten by None, such that the layers can infer the training mode from the context.
:param model_subclass: Keras model of a custom class, which is neither Functional, nor Sequential.
:param dataset: Dataset used to train the model.
:return: Functional Keras model.
"""
input_layers = get_input_layers(dataset)
if 'training' in tf_inspect.getfullargspec(model_subclass.call).args:
model_func = tf.keras.Model(input_layers, model_subclass.call(input_layers, training=None))
else:
model_func = tf.keras.Model(input_layers, model_subclass.call(input_layers))
return model_func
def has_arg(fn, name, accept_all=False):
"""Checks if a callable accepts a given keyword argument.
Args:
fn: Callable to inspect.
name: Check if `fn` can be called with `name` as a keyword argument.
accept_all: What to return if there is no parameter called `name` but the
function accepts a `**kwargs` argument.
Returns:
bool, whether `fn` accepts a `name` keyword argument.
"""
arg_spec = tf_inspect.getfullargspec(fn)
if accept_all and arg_spec.varkw is not None:
return True
return name in arg_spec.args or name in arg_spec.kwonlyargs
def get_training_arg_index(call_fn):
"""Returns the index of 'training' in the layer call function arguments.
Args:
call_fn: Call function.
Returns:
- n: index of 'training' in the call function arguments.
- -1: if 'training' is not found in the arguments, but layer.call accepts
variable keyword arguments
- None: if layer doesn't expect a training argument.
"""
arg_list = tf_inspect.getfullargspec(call_fn).args
if tf_inspect.ismethod(call_fn):
arg_list = arg_list[1:]
if 'training' in arg_list:
return arg_list.index('training')
else:
return -1
def __init__(self, directory, image_data_generator,
target_size=(256, 256),
color_mode='rgb',
classes=None,
class_mode='categorical',
batch_size=32,
shuffle=True,
seed=None,
data_format=None,
save_to_dir=None,
save_prefix='',
save_format='png',
follow_links=False,
subset=None,
interpolation='nearest',
dtype=None):
if data_format is None:
data_format = backend.image_data_format()
kwargs = {}
if 'dtype' in tf_inspect.getfullargspec(
image.ImageDataGenerator.__init__)[0]:
if dtype is None:
dtype = backend.floatx()
kwargs['dtype'] = dtype
super(DirectoryIterator, self).__init__(
directory, image_data_generator,
target_size=target_size,
color_mode=color_mode,
classes=classes,
class_mode=class_mode,
batch_size=batch_size,
shuffle=shuffle,
seed=seed,
data_format=data_format,
save_to_dir=save_to_dir,
save_prefix=save_prefix,
save_format=save_format,
follow_links=follow_links,
subset=subset,
interpolation=interpolation,
**kwargs)
def _has_kwargs(fn):
"""Returns whether the passed callable has **kwargs in its signature.
Args:
fn: Function, or function-like object (e.g., result of `functools.partial`).
Returns:
`bool`: if `fn` has **kwargs in its signature.
Raises:
`TypeError`: If fn is not a Function, or function-like object.
"""
if isinstance(fn, functools.partial):
fn = fn.func
elif _is_callable_object(fn):
fn = fn.__call__
elif not callable(fn):
raise TypeError(
"fn should be a function-like object, but is of type {}.".format(
type(fn)))
return tf_inspect.getfullargspec(fn).varkw is not None
def array_to_img(x, data_format=None, scale=True, dtype=None):
"""Converts a 3D Numpy array to a PIL Image instance.
Usage:
```python
from PIL import Image
img = np.random.random(size=(100, 100, 3))
pil_img = tf.keras.preprocessing.image.array_to_img(img)
```
Args:
x: Input data, in any form that can be converted to a Numpy array.
data_format: Image data format, can be either "channels_first" or
"channels_last". Defaults to `None`, in which case the global setting
`tf.keras.backend.image_data_format()` is used (unless you changed it,
it defaults to "channels_last").
scale: Whether to rescale the image such that minimum and maximum values
are 0 and 255 respectively. Defaults to `True`.
dtype: Dtype to use. Default to `None`, in which case the global setting
`tf.keras.backend.floatx()` is used (unless you changed it, it defaults
to "float32")
Returns:
A PIL Image instance.
Raises:
ImportError: if PIL is not available.
ValueError: if invalid `x` or `data_format` is passed.
"""
if data_format is None:
data_format = backend.image_data_format()
kwargs = {}
if 'dtype' in tf_inspect.getfullargspec(image.array_to_img)[0]:
if dtype is None:
dtype = backend.floatx()
kwargs['dtype'] = dtype
return image.array_to_img(x, data_format=data_format, scale=scale, **kwargs)
def _maybe_wrap_with_training_arg(self, call_fn, match_layer_training_arg):
"""Wraps call function with added training argument if necessary."""
if not self.layer._expects_training_arg and self._expects_training_arg: # pylint: disable=protected-access
# Add training arg to wrapper function.
arg_spec = tf_inspect.getfullargspec(call_fn)
args = arg_spec.args + ['training']
defaults = list(arg_spec.defaults or [])
defaults.append(False)
new_arg_spec = tf_inspect.FullArgSpec(
args=args,
varargs=arg_spec.varargs,
varkw=arg_spec.varkw,
defaults=defaults,
kwonlyargs=arg_spec.kwonlyargs,
kwonlydefaults=arg_spec.kwonlydefaults,
annotations=arg_spec.annotations)
# Set new training arg index
self._training_arg_index = len(args) - 1
if tf_inspect.ismethod(call_fn):
self._training_arg_index -= 1
def wrap_with_training_arg(*args, **kwargs):
if match_layer_training_arg:
# Remove the training value, since the original call_fn does not
# expect a training arg. Instead, the training value will be
# propagated using the call context created in LayerCall.
args = list(args)
kwargs = kwargs.copy()
utils.remove_training_arg(self._training_arg_index, args,
kwargs)
return call_fn(*args, **kwargs)
return tf_decorator.make_decorator(
target=call_fn,
decorator_func=wrap_with_training_arg,
decorator_argspec=new_arg_spec)
return call_fn
def _recreate_layer_from_config(self, layer, go_backwards=False):
# When recreating the layer from its config, it is possible that the layer
# is a RNN layer that contains custom cells. In this case we inspect the
# layer and pass the custom cell class as part of the `custom_objects`
# argument when calling `from_config`.
# See https://github.com/tensorflow/tensorflow/issues/26581 for more detail.
config = layer.get_config()
if go_backwards:
config['go_backwards'] = not config['go_backwards']
if 'custom_objects' in tf_inspect.getfullargspec(
layer.__class__.from_config).args:
custom_objects = {}
cell = getattr(layer, 'cell', None)
if cell is not None:
custom_objects[cell.__class__.__name__] = cell.__class__
# For StackedRNNCells
stacked_cells = getattr(cell, 'cells', [])
for c in stacked_cells:
custom_objects[c.__class__.__name__] = c.__class__
return layer.__class__.from_config(config, custom_objects=custom_objects)
else:
return layer.__class__.from_config(config)
def img_to_array(img, data_format=None, dtype=None):
"""Converts a PIL Image instance to a Numpy array.
Usage:
```python
from PIL import Image
img_data = np.random.random(size=(100, 100, 3))
img = tf.keras.preprocessing.image.array_to_img(img_data)
array = tf.keras.preprocessing.image.img_to_array(img)
```
Args:
img: Input PIL Image instance.
data_format: Image data format, can be either "channels_first" or
"channels_last". Defaults to `None`, in which case the global setting
`tf.keras.backend.image_data_format()` is used (unless you changed it,
it defaults to "channels_last").
dtype: Dtype to use. Default to `None`, in which case the global setting
`tf.keras.backend.floatx()` is used (unless you changed it, it defaults
to "float32")
Returns:
A 3D Numpy array.
Raises:
ValueError: if invalid `img` or `data_format` is passed.
"""
if data_format is None:
data_format = backend.image_data_format()
kwargs = {}
if 'dtype' in tf_inspect.getfullargspec(image.img_to_array)[0]:
if dtype is None:
dtype = backend.floatx()
kwargs['dtype'] = dtype
return image.img_to_array(img, data_format=data_format, **kwargs)
def maybe_add_training_arg(original_call, wrapped_call, expects_training_arg,
default_training_value):
"""Decorate call and optionally adds training argument.
If a layer expects a training argument, this function ensures that 'training'
is present in the layer args or kwonly args, with the default training value.
Args:
original_call: Original call function.
wrapped_call: Wrapped call function.
expects_training_arg: Whether to include 'training' argument.
default_training_value: Default value of the training kwarg to include in
the arg spec. If `None`, the default is `K.learning_phase()`.
Returns:
Tuple of (
function that calls `wrapped_call` and sets the training arg,
Argspec of returned function or `None` if the argspec is unchanged)
"""
if not expects_training_arg:
return wrapped_call, None
def wrap_with_training_arg(*args, **kwargs):
"""Wrap the `wrapped_call` function, and set training argument."""
training_arg_index = get_training_arg_index(original_call)
training = get_training_arg(training_arg_index, args, kwargs)
if training is None:
training = default_training_value or K.learning_phase()
args = list(args)
kwargs = kwargs.copy()
def replace_training_and_call(training):
set_training_arg(training, training_arg_index, args, kwargs)
return wrapped_call(*args, **kwargs)
return control_flow_util.smart_cond(
training, lambda: replace_training_and_call(True),
lambda: replace_training_and_call(False))
# Create arg spec for decorated function. If 'training' is not defined in the
# args of the original arg spec, then add it to kwonlyargs.
arg_spec = tf_inspect.getfullargspec(original_call)
defaults = list(arg_spec.defaults) if arg_spec.defaults is not None else []
kwonlyargs = arg_spec.kwonlyargs
kwonlydefaults = arg_spec.kwonlydefaults or {}
# Add training arg if it does not exist, or set the default training value.
if 'training' not in arg_spec.args:
kwonlyargs.append('training')
kwonlydefaults['training'] = default_training_value
else:
index = arg_spec.args.index('training')
training_default_index = len(arg_spec.args) - index
if (arg_spec.defaults
and len(arg_spec.defaults) >= training_default_index
and defaults[-training_default_index] is None):
defaults[-training_default_index] = default_training_value
decorator_argspec = tf_inspect.FullArgSpec(
args=arg_spec.args,
varargs=arg_spec.varargs,
varkw=arg_spec.varkw,
defaults=defaults,
kwonlyargs=kwonlyargs,
kwonlydefaults=kwonlydefaults,
annotations=arg_spec.annotations)
return wrap_with_training_arg, decorator_argspec
def add(self, layer):
"""Adds a layer instance on top of the layer stack.
Args:
layer: layer instance.
Raises:
TypeError: If `layer` is not a layer instance.
ValueError: In case the `layer` argument does not
know its input shape.
ValueError: In case the `layer` argument has
multiple output tensors, or is already connected
somewhere else (forbidden in `Sequential` models).
"""
# If we are passed a Keras tensor created by keras.Input(), we can extract
# the input layer from its keras history and use that without any loss of
# generality.
if hasattr(layer, '_keras_history'):
origin_layer = layer._keras_history[0]
if isinstance(origin_layer, input_layer.InputLayer):
layer = origin_layer
logging.warning(
'Please add `keras.layers.InputLayer` instead of `keras.Input` to '
'Sequential model. `keras.Input` is intended to be used by '
'Functional model.')
if isinstance(layer, module.Module):
if not isinstance(layer, base_layer.Layer):
layer = functional.ModuleWrapper(layer)
else:
raise TypeError('The added layer must be '
'an instance of class Layer. '
'Found: ' + str(layer))
tf_utils.assert_no_legacy_layers([layer])
if not self._is_layer_name_unique(layer):
raise ValueError('All layers added to a Sequential model '
'should have unique names. Name "%s" is already the name'
' of a layer in this model. Update the `name` argument '
'to pass a unique name.' % (layer.name,))
self.built = False
set_inputs = False
self._maybe_create_attribute('_self_tracked_trackables', [])
if not self._self_tracked_trackables:
if isinstance(layer, input_layer.InputLayer):
# Case where the user passes an Input or InputLayer layer via `add`.
set_inputs = True
else:
batch_shape, dtype = training_utils.get_input_shape_and_dtype(layer)
if batch_shape:
# Instantiate an input layer.
x = input_layer.Input(
batch_shape=batch_shape, dtype=dtype, name=layer.name + '_input')
# This will build the current layer
# and create the node connecting the current layer
# to the input layer we just created.
layer(x)
set_inputs = True
if set_inputs:
outputs = nest.flatten(layer._inbound_nodes[-1].outputs)
if len(outputs) != 1:
raise ValueError(SINGLE_LAYER_OUTPUT_ERROR_MSG)
self.outputs = outputs
self.inputs = layer_utils.get_source_inputs(self.outputs[0])
self.built = True
self._has_explicit_input_shape = True
elif self.outputs:
# If the model is being built continuously on top of an input layer:
# refresh its output.
output_tensor = layer(self.outputs[0])
if len(nest.flatten(output_tensor)) != 1:
raise ValueError(SINGLE_LAYER_OUTPUT_ERROR_MSG)
self.outputs = [output_tensor]
self.built = True
if set_inputs or self._graph_initialized:
self._init_graph_network(self.inputs, self.outputs)
self._graph_initialized = True
else:
self._self_tracked_trackables.append(layer)
self._handle_deferred_layer_dependencies([layer])
self._layer_call_argspecs[layer] = tf_inspect.getfullargspec(layer.call)
def assert_training_default(fn, default_value):
arg_spec = tf_inspect.getfullargspec(fn)
index = len(arg_spec.args) - arg_spec.args.index('training')
self.assertEqual(arg_spec.defaults[-index], default_value)
def deserialize_keras_object(identifier,
module_objects=None,
custom_objects=None,
printable_module_name='object'):
"""Turns the serialized form of a Keras object back into an actual object.
This function is for mid-level library implementers rather than end users.
Importantly, this utility requires you to provide the dict of `module_objects`
to use for looking up the object config; this is not populated by default.
If you need a deserialization utility that has preexisting knowledge of
built-in Keras objects, use e.g. `keras.layers.deserialize(config)`,
`keras.metrics.deserialize(config)`, etc.
Calling `deserialize_keras_object` while underneath the
`SharedObjectLoadingScope` context manager will cause any already-seen shared
objects to be returned as-is rather than creating a new object.
Args:
identifier: the serialized form of the object.
module_objects: A dictionary of built-in objects to look the name up in.
Generally, `module_objects` is provided by midlevel library implementers.
custom_objects: A dictionary of custom objects to look the name up in.
Generally, `custom_objects` is provided by the end user.
printable_module_name: A human-readable string representing the type of the
object. Printed in case of exception.
Returns:
The deserialized object.
Example:
A mid-level library implementer might want to implement a utility for
retrieving an object from its config, as such:
```python
def deserialize(config, custom_objects=None):
return deserialize_keras_object(
identifier,
module_objects=globals(),
custom_objects=custom_objects,
name="MyObjectType",
)
```
This is how e.g. `keras.layers.deserialize()` is implemented.
"""
if identifier is None:
return None
if isinstance(identifier, dict):
# In this case we are dealing with a Keras config dictionary.
config = identifier
(cls, cls_config) = class_and_config_for_serialized_keras_object(
config, module_objects, custom_objects, printable_module_name)
# If this object has already been loaded (i.e. it's shared between multiple
# objects), return the already-loaded object.
shared_object_id = config.get(SHARED_OBJECT_KEY)
shared_object = _shared_object_loading_scope().get(shared_object_id) # pylint: disable=assignment-from-none
if shared_object is not None:
return shared_object
if hasattr(cls, 'from_config'):
arg_spec = tf_inspect.getfullargspec(cls.from_config)
custom_objects = custom_objects or {}
if 'custom_objects' in arg_spec.args:
deserialized_obj = cls.from_config(
cls_config,
custom_objects=dict(
list(_GLOBAL_CUSTOM_OBJECTS.items()) +
list(custom_objects.items())))
else:
with CustomObjectScope(custom_objects):
deserialized_obj = cls.from_config(cls_config)
else:
# Then `cls` may be a function returning a class.
# in this case by convention `config` holds
# the kwargs of the function.
custom_objects = custom_objects or {}
with CustomObjectScope(custom_objects):
deserialized_obj = cls(**cls_config)
# Add object to shared objects, in case we find it referenced again.
_shared_object_loading_scope().set(shared_object_id, deserialized_obj)
return deserialized_obj
elif isinstance(identifier, str):
object_name = identifier
if custom_objects and object_name in custom_objects:
obj = custom_objects.get(object_name)
elif object_name in _GLOBAL_CUSTOM_OBJECTS:
obj = _GLOBAL_CUSTOM_OBJECTS[object_name]
else:
obj = module_objects.get(object_name)
if obj is None:
raise ValueError(
'Unknown {}: {}. Please ensure this object is '
'passed to the `custom_objects` argument. See '
'https://www.tensorflow.org/guide/keras/save_and_serialize'
'#registering_the_custom_object for details.'.format(
printable_module_name, object_name))
# Classes passed by name are instantiated with no args, functions are
# returned as-is.
if tf_inspect.isclass(obj):
return obj()
return obj
elif tf_inspect.isfunction(identifier):
# If a function has already been deserialized, return as is.
return identifier
else:
raise ValueError('Could not interpret serialized %s: %s' %
(printable_module_name, identifier))