code: func (d *ModuleDiff) ChangeType() DiffChangeType {
  	result := DiffNone
  	for _, r := range d.Resources {
  		change := r.ChangeType()
  		switch change {
  		case DiffCreate, DiffDestroy:
  			if result == DiffNone {
  				result = change
  			}
  		case DiffDestroyCreate, DiffUpdate:
  			result = DiffUpdate
  		}
  	}
  
  	return result
  }
docs: // ChangeType returns the type of changes that the diff for this
  // module includes.
  //
  // At a module level, this will only be DiffNone, DiffUpdate, DiffDestroy, or
  // DiffCreate. If an instance within the module has a DiffDestroyCreate
  // then this will register as a DiffCreate for a module.