code: public function offsetSet( $offset, $data ) {
  		if ( is_array( $data ) ) {
  			$data = new self( $data );
  		}
  		if ( $offset === null ) { // don't forget this!
  			$this->container[] = $data;
  		} else {
  			$this->container[ $offset ] = $data;
  		}
  		$this->dirty = true;
  	}
docs: Offset to set
  
  @link http://php.net/manual/en/arrayaccess.offsetset.php
  
  @param mixed $offset The offset to assign the value to.
  @param mixed $value  The value to set.
  
  @return void