docs: def signature_required(secret_key_func):
      """
      Requires that the request contain a valid signature to gain access
      to a specified resource.
      """
      def actual_decorator(obj):
  
          def test_func(request, *args, **kwargs):
              secret_key = secret_key_func(request, *args, **kwargs)
              return validate_signature(request, secret_key)
  
          decorator = request_passes_test(test_func)
          return wrap_object(obj, decorator)
  
      return actual_decorator