code: def _process_map_rule(self, line):
          
          result = self.REPLACE_REGEX.match(line)
          if result is not None:
              what = self._process_first_group(result.group(1))
              replacement = self._process_second_group(result.group(2))
              for char in what:
                  self.trans_map[char] = replacement
                  self.log([u"Adding rule: replace '%s' with '%s'", char, replacement])
          else:
              result = self.DELETE_REGEX.match(line)
              if result is not None:
                  what = self._process_first_group(result.group(1))
                  for char in what:
                      self.trans_map[char] = ""
                      self.log([u"Adding rule: delete '%s'", char])
docs: Process the line string containing a map rule.