code: function to_kwargs(args, sortedKeys)
  {
      var s = '';
      if (!sortedKeys) {
          var sortedKeys = keys(args).sort();
      }
      for (var i = 0; i < sortedKeys.length; ++i) {
          var k = sortedKeys[i];
          if (args[k] != undefined) {
              if (s) {
                  s += ', ';
              }
              s += k + '=' + args[k];
          }
      }
      return s;
  }
docs: Creates a python-style keyword arguments string from an object.
  
  @param args        an associative array mapping strings to strings
  @param sortedKeys  (optional) a list of keys of the args parameter that
  specifies the order in which the arguments will appear in
  the returned kwargs string
  
  @return            a kwarg string representation of args