def __init__(self, config, hparams=None):
    """Initializes the dense prediction cell.

    Args:
      config: A dictionary storing the architecture of a dense prediction cell.
      hparams: A dictionary of hyper-parameters, provided by users. This
        dictionary will be used to update the default dictionary returned by
        dense_prediction_cell_hparams().

    Raises:
       ValueError: If `conv_rate_multiplier` has value < 1.
    """
    self.hparams = dense_prediction_cell_hparams()
    if hparams is not None:
      self.hparams.update(hparams)
    self.config = config

    # Check values in hparams are valid or not.
    if self.hparams['conv_rate_multiplier'] < 1:
      raise ValueError('conv_rate_multiplier cannot have value < 1.')