def get_subnet_cidr(self, subnet_id):
try:<EOL><INDENT>subnet_list = self.neutronclient.list_subnets(id=subnet_id)<EOL>subnet_dat = subnet_list.get('<STR_LIT>')[<NUM_LIT:0>]<EOL>return subnet_dat.get('<STR_LIT>')<EOL><DEDENT>except Exception as exc:<EOL><INDENT>LOG.error("<STR_LIT>"<EOL>"<STR_LIT>", {'<STR_LIT>': subnet_id, '<STR_LIT>': exc})<EOL>return None<EOL><DEDENT>
retrieve the CIDR associated with a subnet, given its ID.