<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def search_by_user(self, screen_name, count=100):
 """Search tweets by user. Args: screen_name: screen name count: the number of tweets Returns: list: tweet list """

        results = self._api.user_timeline(screen_name=screen_name, count=count)

        return results