  
      def to_internal_value(self, data):
          return [
              self.child_relation.to_internal_value(item)
              for item in data
          ]
  
      def get_attribute(self, instance):
 
</s> remove         (['1', '2', '3'], [1, 2, 3])
 </s> add         (['1', '2', '3'], [1, 2, 3]),
        ([], [])
        if isinstance(data, type('')) or not hasattr(data, '__iter__'):
            self.fail('not_a_list', input_type=type(data).__name__)
        if not self.allow_empty and len(data) == 0:
            self.fail('empty')

  
      def to_internal_value(self, data):
        if isinstance(data, type('')) or not hasattr(data, '__iter__'):
            self.fail('not_a_list', input_type=type(data).__name__)
        if not self.allow_empty and len(data) == 0:
            self.fail('empty')

          return [
              self.child_relation.to_internal_value(item)
              for item in data
          ]
  
      def get_attribute(self, instance):
keep add keep keep keep keep keep keep
 Added allow_empty flag for ListField, ListSerializer, ManyRelation, MultipleChoiceField. 
rest_framework/relations.py