code: function(num) {
        if(isUndefined(num)) return this[this.length - 1];
        var start = this.length - num < 0 ? 0 : this.length - num;
        return this.slice(start);
      }
docs: *
  @method last([num] = 1)
  @returns Mixed
  @short Returns the last element(s) in the array.
  @extra When <num> is passed, returns the last <num> elements in the array.
  @example
  
  [1,2,3].last()        -> 3
  [1,2,3].last(2)       -> [2,3]
  
  *