def update(self,
user: User,
video: Video,
watch_time: float,
gamma: float = 0.05):
""" Updates the environment
:param user: user
:param video: video recommended to the user
:param watch_time: effective watch time of the video by the user
:param gamma: evolution parameter (learning rate)
"""
# Type-checking
if not isinstance(user, User):
raise TypeError
if not isinstance(video, Video):
raise TypeError
if not isinstance(watch_time, float):
raise TypeError
if not isinstance(gamma, float):
raise TypeError
user.add_to_history(video.video_id, watch_time) # history update
if self.evolutive: # if the environment is evolutive,
user.evolve(video, watch_time, gamma) # the user tastes can evolve
