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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 get_csrf_token(response):
 """ Extract the CSRF token out of the "Set-Cookie" header of a response. """

    cookie_headers = [
        h.decode('ascii') for h in response.headers.getlist("Set-Cookie")
    ]
    if not cookie_headers:
        return None
    csrf_headers = [
        h for h in cookie_headers if h.startswith("csrftoken=")
    ]
    if not csrf_headers:
        return None
    match = re.match("csrftoken=([^ ;]+);", csrf_headers[-1])
    return match.group(1)