docs: def pre_handler(self, cmd):
          """Hook for logic before each handler starts."""
          if self._finished:
              return
          if self.interesting_commit and cmd.name == 'commit':
              if cmd.mark == self.interesting_commit:
                  print(cmd.to_string())
                  self._finished = True
              return
          if cmd.name in self.parsed_params:
              fields = self.parsed_params[cmd.name]
              str = cmd.dump_str(fields, self.parsed_params, self.verbose)
              print("%s" % (str,))