code: def get_group_name_nonetrick(self, group_name = None):
          
          groups = self.m["groups"]
          if (len(groups) == 0):
              raise Exception("Cannot find any groups in metadata")
          if (not group_name):
              if (len(groups) > 1):
                  raise Exception("We have more than one payment group in metadata, so group_name should be specified")
              return groups[0]["group_name"]
          return group_name
docs: In all getter function in case of single payment group, group_name can be None