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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_raw_token(self, header):
 """ Extracts an unvalidated JSON web token from the given "Authorization" header value. """

        parts = header.split()

        if len(parts) == 0:
            # Empty AUTHORIZATION header sent
            return None

        if parts[0] not in AUTH_HEADER_TYPE_BYTES:
            # Assume the header does not contain a JSON web token
            return None

        if len(parts) != 2:
            raise AuthenticationFailed(
                _('Authorization header must contain two space-delimited values'),
                code='bad_authorization_header',
            )

        return parts[1]