the memory sequence (optional).
     * **tgt_key_padding_mask** (*Optional**[**Tensor**]*) -- the
       mask for the tgt keys per batch (optional).

     * **memory_key_padding_mask** (*Optional**[**Tensor**]*) --
       the mask for the memory keys per batch (optional).

     * **tgt_is_causal** (*bool*) -- If specified, applies a
       causal mask as tgt mask. Mutually exclusive with providing
       tgt_mask. Default: "False".

     * **memory_is_causal** (*bool*) -- If specified, applies a
       causal mask as tgt mask. Mutually exclusive with providing
       memory_mask. Default: "False".

  Return type:
     *Tensor*

  Shape:
     see the docs in Transformer class.
