code: function(box, units) {
              var a = this.addUnits,
                  b = this.parseBox(box);
  
              return a(b.top, units) + ' ' +
                     a(b.right, units) + ' ' +
                     a(b.bottom, units) + ' ' +
                     a(b.left, units);
  
          }
docs: Parses a number or string representing margin sizes into an object. Supports CSS-style margin declarations
  (e.g. 10, "10", "10 10", "10 10 10" and "10 10 10 10" are all valid options and would return the same result)
  @static
  @param {Number/String/Object} box The encoded margins, or an object with top, right,
  bottom, and left properties
  @param {String} units The type of units to add
  @return {String} An string with unitized (px if units is not specified) metrics for top, right, bottom and left