Function _GetCellGrad

Returns the gradient function for cell_fn. Args: cell_fn: The recurrent neural net's cell function. cell_grad: If not None, cell_fn's gradient function. theta: weights. A `.NestedMap`. state0: initial state. A `.NestedMap`. inputs: inputs. A `.NestedMap`. accumulator_layer

(cell_fn,
                 cell_grad,
                 theta,
                 state0,
                 inputs,
                 accumulator_layer,
                 check_stateful_ops=False,
                 allow_implicit_capture=False,
                 allowed_tensor_captures=None)