private static function callbackEquals( $callback1, $callback2 ) {

			if ( is_array( $callback1 ) && is_array( $callback2 ) ) {
				
				if ( count( $callback1 ) == count( $callback2 ) ) {
				
					for ( $i=0, $len = count( $callback1 ); $i<$len; $i++ ) {
						if ( $callback1[$i] != $callback2[$i] ) {
							return false;
						}
					}

					return true;

				} else {
					
					return false;
				
				}

			} else {

				return $callback1 == $callback2;

			}

		}