code: function parse_containers($containers)
  	{
  		// Construct an array of container names
  		if (!is_array($containers)) {
  			$containers = explode(',', $containers);
  		}
  		// Parse each container
  		foreach ($containers as $container) {
  			$masktree = $this->read_container($container, _ETS_ROOT);
  			if ($masktree === FALSE) {
  				$this->error(11, 52, $this->container);
  			} else {
  				$this->masktree = $this->masktree_merge($this->masktree, $masktree, $container);
  			}
  		}
  	}
docs: Read containers then parse their content to build a template tree