code: function wrap (wrapper, callback) {
        return _.bind(function wrapped () {
          var args = _.toArray(arguments).concat([callback]);
          return wrapper.apply(this, args);
        }, this);
      }
docs: Internal helper function used to create function wrappers. Like _.wrap, except for the following differences: - wrapped ``callback`` function is last argument, as per convention - ``wrapper`` is expected to take ``callback`` function last, as per convention. - returned function is bound to ``this`` instance. Expects the following arguments: ``callback`` (function): function to be wrapped ``wrapper`` (function): wrapper function responsible for executing ``callback`` with appropriate arguments. Accepts these arguments: ``arguments`` - should accept all the arguments of ``callback`` ``callback`` (function): wrapped function