old_contents: # -*- coding: utf-8 -*-
  from datetime import datetime, timedelta
  
  USER_CACHE_MAX = 10
  MONTH_FMT = '%Y/%m'
  DAY_FMT = '%Y/%m/%d'
  
  
  def month_last(month_str):
      day_str = '%s/10' % month_str
      dt = datetime.strptime(day_str, DAY_FMT)
      new_dt = dt + timedelta(days=-20)
      return datetime.strftime(new_dt, MONTH_FMT)
  
new_contents: # -*- coding: utf-8 -*-
  from datetime import datetime, timedelta
  
  USER_CACHE_MAX = 1000
  MONTH_FMT = '%Y/%m'
  DAY_FMT = '%Y/%m/%d'
  
  
  def month_last(month_str):
      day_str = '%s/10' % month_str
      dt = datetime.strptime(day_str, DAY_FMT)
      new_dt = dt + timedelta(days=-20)
      return datetime.strftime(new_dt, MONTH_FMT)
  
subject: fix a debug parameter