code: def _add_cmd_output(self, cmd, suggest_filename=None,
                          root_symlink=None, timeout=300, stderr=True,
                          chroot=True, runat=None, env=None, binary=False,
                          sizelimit=None, pred=None):
          
          cmdt = (
              cmd, suggest_filename,
              root_symlink, timeout, stderr,
              chroot, runat, env, binary, sizelimit
          )
          _tuplefmt = ("('%s', '%s', '%s', %s, '%s', '%s', '%s', '%s', '%s', "
                       "'%s')")
          _logstr = "packed command tuple: " + _tuplefmt
          self._log_debug(_logstr % cmdt)
          if self.test_predicate(cmd=True, pred=pred):
              self.collect_cmds.append(cmdt)
              self._log_info("added cmd output '%s'" % cmd)
          else:
              self._log_info("skipped cmd output '%s' due to predicate (%s)" %
                             (cmd, self.get_predicate(cmd=True, pred=pred)))
docs: Internal helper to add a single command to the collection list.