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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_authenticate_header(self, request):
 """ If a request is unauthenticated, determine the WWW-Authenticate header to use for 401 responses, if any. """

        authenticators = self.get_authenticators()
        if authenticators:
            return authenticators[0].authenticate_header(request)