code: function alias($names) : self {
          if (!isset($this->_pSet)) {
              Console::warning("No route to alias.");
              return $this;
          }
          if (!is_array($names))
              $names = [$names];
          foreach ($names as $name) {
              if (isset($this->_alias[$name]))
                  Console::warning("Overwriting route alias \"$name\".");
              $this->_alias[$name] = &$this->_pSet;
          }
          return $this;
      }
docs: 路由别名，用于实现分发
  
  @param mixed $names
  @return Router