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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def login(self, email=None, password=None, app_id=None, api_key=None):
 """Login to MediaFire account. Keyword arguments: email -- account email password -- account password app_id -- application ID api_key -- API Key (optional) """

        session_token = self.api.user_get_session_token(
            app_id=app_id, email=email, password=password, api_key=api_key)

        # install session token back into api client
        self.api.session = session_token