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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 load_dependencies(req, history=None):
 """ Load the dependency tree as a Python object tree, suitable for JSON serialization. """

    if history is None:
        history = set()
    dist = pkg_resources.get_distribution(req)
    spec = dict(
        requirement=str(req),
        resolved=str(dist),
    )
    if req not in history:
        # traverse into children
        history.add(req)
        extras = parse_extras(req)
        depends = [
            load_dependencies(dep, history=history)
            for dep in dist.requires(extras=extras)
        ]
        if depends:
            spec.update(depends=depends)
    return spec