<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _match_exists(self, searchable):
 """Make sure the searchable description doesn't already exist """

        position_searchable = self.get_position_searchable()
        for pos,val in position_searchable.iteritems():
            if val == searchable:
                return pos
        return False