code: function createOpenTag (tagName, attrs) {
    var attrString = Object.keys(attrs).map(function (key) {
      return ' ' + key + '="' + attrs[key] + '"';
    }).join('');
  
    return '<' + tagName + attrString + '>';
  }
docs: Creates an opening XML tag based on tagName and attributes
  
  @param tagName
  @param attrs
  @returns {string}