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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def convert_sum(node, **kwargs):
 """Map MXNet's sum operator attributes to onnx's ReduceSum operator and return the created node. """

    name, input_nodes, attrs = get_inputs(node, kwargs)

    mx_axis = attrs.get("axis", None)
    axes = convert_string_to_list(str(mx_axis)) if mx_axis is not None else None

    keepdims = get_boolean_attribute_value(attrs, "keepdims")

    if axes:
        node = onnx.helper.make_node(
            'ReduceSum',
            inputs=input_nodes,
            outputs=[name],
            axes=axes,
            keepdims=keepdims,
            name=name
        )
    else:
        node = onnx.helper.make_node(
            'ReduceSum',
            inputs=input_nodes,
            outputs=[name],
            keepdims=keepdims,
            name=name
        )
    return [node]