<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def delete(self, id):
 """ Deletes document with ID on all Solr cores """

        for core in self.endpoints:
            self._send_solr_command(self.endpoints[core], "{\"delete\" : { \"id\" : \"%s\"}}" % (id,))