docs: function getDistinctValues(mongoHandle, modelname, category) {
      debuglog(() => `here models ${modelname} ` + mongoHandle.mongoose.modelNames().join(';'));
      var model = mongoHandle.mongoose.model(Schemaload.makeMongooseModelName(modelname));
      var mongoMap = mongoHandle.mongoMaps[modelname];
      checkModelMongoMap(model, modelname, mongoMap, category);
      debuglog(' here path for distinct value ' + mongoMap[category].fullpath);
      return model.distinct(mongoMap[category].fullpath).then(res => {
          debuglog(() => ` here res for ${modelname}  ${category} values ` + JSON.stringify(res, undefined, 2));
          return res;
      });
  }