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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 fixup_namespace_packages(path_item, parent=None):
 """Ensure that previously-declared namespace packages include path_item"""

    _imp.acquire_lock()
    try:
        for package in _namespace_packages.get(parent, ()):
            subpath = _handle_ns(package, path_item)
            if subpath:
                fixup_namespace_packages(subpath, package)
    finally:
        _imp.release_lock()