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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 framework_version_from_tag(image_tag):
 """Extract the framework version from the image tag. Args: image_tag (str):
 Image tag, which should take the form '<framework_version>-<device>-<py_version>' Returns: str: The framework version. """

    tag_pattern = re.compile('^(.*)-(cpu|gpu)-(py2|py3)$')
    tag_match = tag_pattern.match(image_tag)
    return None if tag_match is None else tag_match.group(1)