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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 _member_data_key(self, leaderboard_name):
        '''
        Key for retrieving optional member data.

        @param leaderboard_name [String] Name of the leaderboard.
        @return a key in the form of +leaderboard_name:member_data+
        '''
        if self.global_member_data is False:
            return '%s:%s' % (leaderboard_name, self.member_data_namespace)
        else:
            return self.member_data_namespace