配列深さ舗装-flatten

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

new = []
def flatten(lists):
  for s in lists:
    if isinstance(s, list):
      flatten(s)
    else:
      new.append(s)
  return new

items = [1, 2, [3, 4, [5, 6], 7, [8], 9], 10]
newItems = flatten(items)
print(newItems)