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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 extract_imports(script):
 """Extract all imports from a python script"""

    if not os.path.isfile(script):
        raise ValueError('Not a file: %s' % script)
    parse_tree = parse_python(script)
    result = find_imports(parse_tree)
    result.path = script
    return result