def create(cls, user, title, category, exploration_id=None, init_state_name="Activity 1", image_id=None):
"""Creates and returns a new exploration."""
# Generate a new exploration id, if one wasn't passed in.
exploration_id = exploration_id or cls.get_new_id(title)
# Temporarily create a fake initial state key.
state_id = State.get_new_id(init_state_name)
fake_state_key = ndb.Key(Exploration, exploration_id, State, state_id)
# Note that demo explorations do not have owners, so user may be None.
exploration = cls(
id=exploration_id,
title=title,
init_state=fake_state_key,
category=category,
image_id=image_id,
states=[fake_state_key],
editors=[user] if user else [],
)
exploration.put()
# Finally, create the initial state and check that it has the right key.
new_init_state = State.create(exploration, init_state_name, state_id=state_id)
assert fake_state_key == new_init_state.key
return exploration
