def __init__(self, dbh, table_schema, table_name):
    self._dbh = dbh
    self.table_schema = table_schema # Name of the db table resides in.
    self.table_name = table_name # Name of the table.
    self._attrs = {}
    self._attrs['db'] = self.table_schema
    self._attrs['table'] = self.table_name
    db = schema.Database(dbh, self.table_schema)
    self._table = schema.Table(dbh, db, self.table_name)
    if not self._table.GetPrimaryKey():
      raise NoPrimaryKey('Table: %s does not have a primary key.'
                          % self.table_name)
Args:
dataset/ETHPy150Open google/mysql-tools/pylib/range_lib.py/PrimaryKeyRange.__init__