code: function ( obj, arg ) {
  		var result = -1;
  
  		array.each( obj, function ( i, idx ) {
  			if ( i === arg ) {
  				result = idx;
  			}
  		});
  
  		return result;
  	}
docs: Finds the last index of `arg` in `obj`
  
  @method rindex
  @param  {Array} obj Array to search
  @param  {Mixed} arg Primitive to find
  @return {Mixed}     Index or undefined