code: def build_base_filename(self):
          
          if self.stream:
              self.stream.close()
              self.stream = None
  
          # remove old suffix
          if self.suffix_time != "":
              index = self.baseFilename.find("." + self.suffix_time)
              if index == -1:
                  index = self.baseFilename.rfind(".")
              self.baseFilename = self.baseFilename[:index]
  
          # add new suffix
          current_time_tuple = time.localtime()
          self.suffix_time = time.strftime(self.suffix, current_time_tuple)
          self.baseFilename = self.baseFilename + "." + self.suffix_time
  
          self.mode = 'a'
          if not self.delay:
              self.stream = self._open()
docs: do builder; in this case,
          old time stamp is removed from filename and
          a new time stamp is append to the filename