code: def slow_format(self, x, base):
      digits = []
      sign = 0
      if x < 0:
          sign, x = 1, -x
      while x:
          x, r = divmod(x, base)
          digits.append(int(r))
      digits.reverse()
      digits = digits or [0]
      return (
          "-"[:sign]
          + {2: "0b", 8: "0o", 10: "", 16: "0x"}[base]
          + "".join("0123456789abcdef"[i] for i in digits)
      )
  
imports: import unittest
  from test import support
  import sys
  import random
  import math
  import array
label_desc: Use image node_id 10 for calling the LongTest obj's underlying member method code with example usage: obj.slow_format(x, base) and returns: unknown