code: function( runDefaults, el ) {
  					var part = parts.shift();
  					if (!part ) {
  						callback(runDefaults, el);
  						return;
  					}
  					el = el || element;
  					if ( part.length > 1 ) {
  						part = part.substr(1, part.length - 2)
  					}
  					self._key(part, el, runNextPart)
  				}
docs: break it up into parts ... go through each type and run