Map MXNet's expand_dims operator attributes to onnx's Unsqueeze operator
    and return the created node.

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

    axis = int(attrs.get("axis"))

    node = onnx.helper.make_node(
        "Unsqueeze",
        input_nodes,
        [name],
        axes=[axis],
        name=name,
    )
    return [node]