code: function extend(destination) {
    assert(typeof destination === 'object');
  
    function assign(source) {
      if (!source) { return; }
      Object.keys(source).forEach(function(key) {
        var value = source[key];
        if (isValue(value)) {
          destination[key] = value;
        }
      });
    }
  
    for (var i = 1; i < arguments.length; ++i) {
      assign(arguments[i]);
    }
    return destination;
  }
docs: /*
  Extends an object with another
  @param destination {object} - object that will get extended
  @parma source {object} - object the will used to extend source