func_code: def merge_lists(l1, l2):
      l3 = []
      merge = 1
      for num in l1:
          if merge > 0:
              l3.append(num)
          merge = -merge
      merge = 1
      for num in l2:
          if merge > 0:
              l3.append(num)
          merge = -merge
      return l3