code: public function getTheme()
      {
          if (!isset($this->_theme)) {
              return $this->_lastLoadedTheme->object;
          }
          if (!isset($this->_theme)) {
              throw new Exception("No theme has been loaded!");
          }
  
          return $this->_theme;
      }
docs: Get theme.
  
  @throws Exception [[@doctodo exception_description:Exception]]
  @return [[@doctodo return_type:getTheme]] [[@doctodo return_description:getTheme]]