code: function getAttributes(obj) {
      let attrString = '';
      let attrArray = Object.keys(obj);
      for (let tag of attrArray) {
          if (tag != ATTR && ATTRTAG.test(tag)) {
              attrString += ` ${tag.replace('_', '')}="${obj[tag]}"`;
          }
      }
      if (ATTR in obj) {
          attrString += ' ' + obj[ATTR];
      }
      return attrString;
  }
docs: return attribute string