code: def schemas(self):
          
          sql = """SELECT schema_name FROM information_schema.schemata
                   ORDER BY schema_name"""
          schemas = self.query(sql).fetchall()
          return [s[0] for s in schemas if s[0][:3] != "pg_"]
docs: Get a listing of all non-system schemas (prefixed with 'pg_') that
          exist in the database.