correct pyang errors

  import _3gpp-5gc-nrm-udrfunction { prefix udr3gpp; }

  import _3gpp-5gc-nrm-udmfunction { prefix udm3gpp; }

  import _3gpp-5gc-nrm-ausffunction { prefix ausf3gpp; }

  import _3gpp-5gc-nrm-amffunction { prefix amf3gpp;}

  import _3gpp-5gc-nrm-smffunction { prefix smf3gpp;}

  import _3gpp-5gc-nrm-upffunction { prefix upf3gpp;}

  import _3gpp-5gc-nrm-pcffunction { prefix pcf3gpp;}

  organization "3gpp SA5";

  contact "https://www.3gpp.org/DynaReport/TSG-WG--S5--officials.htm?Itemid=464";

  description "This IOC represents the NRF function in 5GC.

        }

        min-elements 1;

        uses AusfInfoGrp;

        uses ausf3gpp:AusfInfoGrp;

      }

      list servedAmfInfo {

        }

        min-elements 1;

        uses amfInfo;

        uses amf3gpp:AmfInfoGrp;

      }

      list servedSmfInfo {

        }

        min-elements 1;

        uses SmfInfoGrp;

        uses smf3gpp:SmfInfoGrp;

      }

      list servedUpfInfo {

        }

        min-elements 1;

        uses upfInfo;

        uses upf3gpp:UpfInfoGrp;

      }

      list servedPcfInfo {

        }

        min-elements 1;

        uses pcfInfo;

        uses pcf3gpp:pcfInfoGrp;

      }

      list servedBsfInfo {