code: def replace_u_end_month(month):
      
      month = month.lstrip('-')
      if month == 'uu' or month == '1u':
          return '12'
      if month == 'u0':
          return '10'
      if month == '0u':
          return '09'
      if month[1] in ['1', '2']:
          # 'u1' or 'u2'
          return month.replace('u', '1')
      # Otherwise it should match r'u[3-9]'.
      return month.replace('u', '0')
docs: Find the latest legitimate month.