def create_from_yaml(
cls, yaml_file, user, title, category, exploration_id=None,
image_id=None):
"""Creates an exploration from a YAML file."""
init_state_name = yaml_file[:yaml_file.find(':\n')]
if not init_state_name or '\n' in init_state_name:
raise Exception('Invalid YAML file: the name of the initial state '
'should be left-aligned on the first line and '
'followed by a colon')
exploration = cls.create(
user, title, category, exploration_id=exploration_id,
init_state_name=init_state_name, image_id=image_id)
init_state = State.get_by_name(init_state_name, exploration)
try:
exploration_dict = utils.dict_from_yaml(yaml_file)
state_list = []
for state_name, state_description in exploration_dict.iteritems():
state = (init_state if state_name == init_state_name
else exploration.add_state(state_name))
state_list.append({'state': state, 'desc': state_description})
for index, state in enumerate(state_list):
State.modify_using_dict(
exploration, state['state'], state['desc'])
except Exception:
exploration.delete()
raise
return exploration
