def change_score_for_member_in(self, leaderboard_name, member, delta, member_data=None):
pipeline = self.redis_connection.pipeline()<EOL>pipeline.zincrby(leaderboard_name, member, delta)<EOL>if member_data:<EOL><INDENT>pipeline.hset(<EOL>self._member_data_key(leaderboard_name),<EOL>member,<EOL>member_data)<EOL><DEDENT>pipeline.execute()<EOL>
Change the score for a member in the named leaderboard by a delta which can be positive or negative.

@param leaderboard_name [String] Name of the leaderboard.
@param member [String] Member name.
@param delta [float] Score change.
@param member_data [String] Optional member data.