code: def diff(a, b):
          
          delta = diff(a, b)
          if not a:
              return delta
          for item in delta:
              if isinstance(a[item], list):
                  if delta[item] == []:
                      delta[item] = {JSONUtils.DIFF_DELETE : a[item]}
                  elif isinstance(delta[item], dict):
                      for key in delta[item].keys():
                          if str(key) == JSONUtils.DIFF_DELETE:
                              delta_upd = {JSONUtils.DIFF_DELETE : []}
                              for i in delta[item][key]:
                                  delta_upd[JSONUtils.DIFF_DELETE].append(a[item][i])
                                  delta[item] = delta_upd
          return delta
docs: Compares JSON objects
          :param a:
          :param b:
          :return: difference object a vs b