code: def _get_changes(self):
          '''Get all changed values.'''
          result = dict( (f['id'], f.get('value','')) for f in self._data if f.get('changed', False) )
          self._clear_changes
          return resulf _get_changes(self):
          '''Get all changed values.'''
          result = dict( (f['id'], f.get('value','')) for f in self._data if f.get('changed', False) )
          self._clear_changes
          return result
docs: Get all changed values.