docs: function ProcessingInstruction(doc, name, content) {
      if (!doc) {
          throw new Error('document argument required');
      } else if (! (doc instanceof bindings.Document)) {
          throw new Error('document argument must be an ' +
                          'instance of Document');
      } else if (!name) {
          throw new Error('name argument required');
      }
  
      return new bindings.ProcessingInstruction(doc, name, content);
  }