code: def dict_merge(a, b, k):
      
      c = a.copy()
      for j in range(len(b)):
          flag = False
          for i in range(len(c)):
              if c[i][k] == b[j][k]:
                  c[i] = b[j].copy()
                  flag = True
          if not flag:
              c.append(b[j].copy())
      return c
docs: Merge two dictionary lists
      :param a: original list
      :param b: alternative list, element will replace the one in original list with same key
      :param k: key
      :return: the merged list