Map MXNet's L2Normalization operator attributes to onnx's LpNormalization operator
    and return the created node.

def convert_l2normalization(node, **kwargs):
    """Map MXNet's L2Normalization operator attributes to onnx's LpNormalization operator
    and return the created node.
    """
    name, input_nodes, attrs = get_inputs(node, kwargs)

    mode = attrs.get("mode", "instance")

    if mode != "channel":
        raise AttributeError("L2Normalization: ONNX currently supports channel mode only")

    l2norm_node = onnx.helper.make_node(
        "LpNormalization",
        input_nodes,
        [name],
        axis=1,  # channel only
        name=name
    )
    return [l2norm_node]