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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 file_extension(path):
 """ Return the file extension. Examples: :: /foo/bar.baz => baz None => None :param string path: the file path :rtype: string """

    if path is None:
        return None
    ext = os.path.splitext(os.path.basename(path))[1]
    if ext.startswith("."):
        ext = ext[1:]
    return ext