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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_url(request):
 """ Since we might be hosted behind a proxy, we need to check the X-Forwarded-Proto, X-Forwarded-Protocol, or X-Forwarded-SSL headers to find out what protocol was used to access us. """

    protocol = request.headers.get('X-Forwarded-Proto') or request.headers.get('X-Forwarded-Protocol')
    if protocol is None and request.headers.get('X-Forwarded-Ssl') == 'on':
        protocol = 'https'
    if protocol is None:
        return request.url
    url = list(urlparse(request.url))
    url[0] = protocol
    return urlunparse(url)