func_code: def union(a, b):
      x = a + b
      while 0 < len(x):
          i = 0
          while i < len(x) and x[i] != x:
              i = i + 1
      if i == len(x):
          d[x[i]] = True
      print(union([1, 2, 3], [3, 4, 5]))