code: function isUpdateDescriptor(descriptor) {
      if (typeof descriptor !== 'object' || !descriptor) {
          return false;
      }
  
      return Object.keys(descriptor).some(op => op in UPDATE_OPS);
  }
docs: Checks whether the given object is Mongo update descriptor or not.
  
  @param {*} descriptor Candidate descriptor being checked
  @returns {boolean}