code: function pbxBuildFileObj(file) {
      var obj = Object.create(null);
  
      obj.isa = 'PBXBuildFile';
      obj.fileRef = file.fileRef;
      obj.fileRef_comment = file.basename;
      if (file.settings) obj.settings = file.settings;
  
      return obj;
  }
docs: helper object creation functions