zeros
  * **check_batched_grad** (*bool**, **optional*) -- if True,
    check if we can compute batched gradients using prototype vmap
    support. Defaults to False.

  * **fast_mode** (*bool**, **optional*) -- if True, run a faster
    implementation of gradgradcheck that no longer computes the
    entire jacobian.

Returns:
      True if all differences satisfy allclose condition
Return type:
      bool