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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 parse_auth_token_from_request(self, auth_header):
 """ Parses and returns the Hawk Authorization header if it is present and well-formed. Raises `falcon.HTTPUnauthoried exception` with proper error message """

        if not auth_header:
            raise falcon.HTTPUnauthorized(
                description='Missing Authorization Header')

        try:
            auth_header_prefix, _ = auth_header.split(' ', 1)
        except ValueError:
            raise falcon.HTTPUnauthorized(
                description='Invalid Authorization Header: Missing Scheme or Parameters')

        if auth_header_prefix.lower() != self.auth_header_prefix.lower():
            raise falcon.HTTPUnauthorized(
                description='Invalid Authorization Header: '
                            'Must start with {0}'.format(self.auth_header_prefix))

        return auth_header