def _get_value_for_attr(
obj,
cls,
orig_cls,
sig_key,
sig,
meta_hints,
attr_getters,
**kwargs):
# Find a value for the attribute (with signature sig_key).
if obj and sig_key in obj:
# This argument is in obj.
result = sig_key, _get_value_from_obj(obj, cls, sig, sig_key,
meta_hints, **kwargs)
elif sig_key in attr_getters:
# There exists an attr_getter for this argument.
attr_getter = attr_getters.pop(sig_key)
result = sig_key, attr_getter()
elif sig.default != inspect.Parameter.empty:
# There is a default value for this argument.
result = sig_key, sig.default
elif sig.kind in (inspect.Parameter.VAR_POSITIONAL,
inspect.Parameter.VAR_KEYWORD):
# This argument is either *args or **kwargs.
result = None, None
elif can_match_with_none(cls):
# It is fine that there is no value.
result = sig_key, None
else:
raise UnfulfilledArgumentError(
'No value found for "{}"'.format(sig_key), sig_key, obj, orig_cls)
return result
def _check_for_none(json_obj: object, cls: type):
# Check if the json_obj is None and whether or not that is fine.
if json_obj is None and not can_match_with_none(cls):
cls_name = get_class_name(cls).lower()
raise DeserializationError(
message='NoneType cannot be deserialized into {}'.format(cls_name),
source=json_obj,
target=cls)