func_code: def minimum(s):
      if len(s) == 0:
          return 0
      else:
          min_ret = minimum(s[1:])
          return s[0] if s[0] < min_ret else min_ret
annotation: def minimum(s):
      if len(s) == 1:
          return s[0]
      else:
          min_ret = minimum(s[1:])
          return s[0] if s[0] < min_ret else min_ret
  