'Look in the \'ddl runner\' for \'memos\', then
note our name in that collection.
This to ensure a particular named enum is operated
upon only once within any kind of create/drop
sequence without relying upon "checkfirst".'

def _check_for_name_in_memos(self, checkfirst, kw):

    if (not self.create_type):
        return True
    if ('_ddl_runner' in kw):
        ddl_runner = kw['_ddl_runner']
        if ('_pg_enums' in ddl_runner.memo):
            pg_enums = ddl_runner.memo['_pg_enums']
        else:
            pg_enums = ddl_runner.memo['_pg_enums'] = set()
        present = (self.name in pg_enums)
        pg_enums.add(self.name)
        return present
    else:
        return False
