for details.  Default: "False"
  * **dropout** -- If non-zero, introduces a *Dropout* layer on
    the outputs of each GRU layer except the last layer, with
    dropout probability equal to "dropout". Default: 0

  * **bidirectional** -- If "True", becomes a bidirectional GRU.
    Default: "False"

Inputs: input, h_0
      * input: tensor of shape (L, H_{in}) for unbatched input,
        (L, N, H_{in}) when "batch_first=False" or (N, L, H_{in}) when
        "batch_first=True" containing the features of the input
        sequence.  The input can also be a packed variable length
        sequence. See "torch.nn.utils.rnn.pack_padded_sequence()" or
        "torch.nn.utils.rnn.pack_sequence()" for details.
  * **h_0**: tensor of shape (D * \text{num\_layers}, H_{out}) or
    (D * \text{num\_layers}, N, H_{out}) containing the initial
    hidden state for the input sequence. Defaults to zeros if not
    provided.

  where:
