code: def r_cts(self):
          
          _request = request.args.get("request", None)
          if _request is not None:
              try:
                  if _request.lower() == "getcapabilities":
                      return self._get_capabilities(
                          urn=request.args.get("urn", None)
                      )
                  elif _request.lower() == "getpassage":
                      return self._get_passage(
                          urn=request.args.get("urn", None)
                      )
                  elif _request.lower() == "getpassageplus":
                      return self._get_passage_plus(
                          urn=request.args.get("urn", None)
                      )
                  elif _request.lower() == "getlabel":
                      return self._get_label(
                          urn=request.args.get("urn", None)
                      )
                  elif _request.lower() == "getfirsturn":
                      return self._get_first_urn(
                          urn=request.args.get("urn", None)
                      )
                  elif _request.lower() == "getprevnexturn":
                      return self._get_prev_next(
                          urn=request.args.get("urn", None)
                      )
                  elif _request.lower() == "getvalidreff":
                      return self._get_valid_reff(
                          urn=request.args.get("urn", None),
                          level=request.args.get("level", 1, type=int)
                      )
              except NautilusError as E:
                  return self.cts_error(error_name=E.__class__.__name__, message=E.__doc__)
          return self.cts_error(MissingParameter.__name__, message=MissingParameter.__doc__)
docs: Actual main route of CTS APIs. Transfer typical requests through the ?request=REQUESTNAME route
  
          :return: Response