<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _elect_source_replication_group( self, over_replicated_rgs, partition, ):
 """Decide source replication-group based as group with highest replica count. """

        return max(
            over_replicated_rgs,
            key=lambda rg: rg.count_replica(partition),
        )