Map MXNet's softmax operator attributes to onnx's Softmax operator
    and return the created node.

def convert_softmax(node, **kwargs):
    """Map MXNet's softmax operator attributes to onnx's Softmax operator
    and return the created node.
    """
    name, input_nodes, attrs = get_inputs(node, kwargs)

    axis = int(attrs.get("axis", -1))

    softmax_node = onnx.helper.make_node(
        "Softmax",
        input_nodes,
        [name],
        axis=axis,
        name=name
    )

    return [softmax_node]