def __init__(self, ctx, op_defs):
    super(TFRGen, self).__init__(ctx)
    self.ctx = ctx
    self.symbol_table = SymbolTable()
    self._op_defs = op_defs

  def _create_mlir_loc(self, loc):
    """Creates mlir location from autograph ORIGIN value.

    Args:
      loc: OriginInfo

    Returns:
      A serialized mlir location string.
    """