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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 delete_user_avatar(self, username, avatar):
 """Delete a user's avatar. :param username: the user to delete the avatar from :param avatar: ID of the avatar to remove """

        params = {'username': username}
        url = self._get_url('user/avatar/' + avatar)
        return self._session.delete(url, params=params)