  
  
  class TimeField(Field):
      default_error_messages = {
          'invalid': _("Time has wrong format. Use one of these formats instead: %s"),
      }
      input_formats = api_settings.TIME_INPUT_FORMATS
      format = api_settings.TIME_FORMAT
  
      def __init__(self, input_formats=None, format=None, *args, **kwargs):
 
</s> remove         'invalid': _("Datetime has wrong format. Use one of these formats instead: %s"),
 </s> add         'invalid': _('Datetime has wrong format. Use one of these formats instead: {format}'), </s> remove         'invalid': _("Date has wrong format. Use one of these formats instead: %s"),
 </s> add         'invalid': _('Date has wrong format. Use one of these formats instead: {format}'), </s> remove     childs = serializers.PrimaryKeyRelatedField(many=True, source='childs')
 </s> add     childs = serializers.PrimaryKeyRelatedField(
        many=True, queryset=ClassB.objects.all()
    ) </s> remove def get_default_queryset(serializer_class, field_name):
    manager = getattr(serializer_class.opts.model, field_name)
    if hasattr(manager, 'related'):
        # Forward relationships
        return manager.related.model._default_manager.all()
    # Reverse relationships
    return manager.field.rel.to._default_manager.all()


 </s> add 
        'invalid': _('Time has wrong format. Use one of these formats instead: {format}'),
  
  
  class TimeField(Field):
      default_error_messages = {
        'invalid': _('Time has wrong format. Use one of these formats instead: {format}'),
      }
      input_formats = api_settings.TIME_INPUT_FORMATS
      format = api_settings.TIME_FORMAT
  
      def __init__(self, input_formats=None, format=None, *args, **kwargs):
keep keep keep keep replace keep keep keep keep keep
 Clean up relational fields queryset usage 
rest_framework/fields.py