          self.queryset = queryset
          self.fields = fields
          self.serializer_field = None
  
      def __call__(self, value):
          serializer = self.serializer_field
  
          # Determine the existing instance, if this is an update operation.
          instance = getattr(serializer, 'instance', None)
  
          # Ensure uniqueness.
          filter_kwargs = dict([
 
</s> remove         instance = getattr(serializer, 'instance', None)
 </s> add         self.instance = getattr(serializer, 'instance', None) </s> remove     def __call__(self, value):
        field = self.serializer_field

        # Determine the model field name that the serializer field corresponds to.
        field_name = field.source_attrs[0] if field.source_attrs else field.field_name

 </s> add     def set_context(self, serializer_field):
        # Determine the underlying model field name. This may not be the
        # same as the serializer field name if `source=<>` is set.
        self.field_name = serializer_field.source_attrs[0] </s> remove         instance = getattr(field.parent, 'instance', None)
 </s> add         self.instance = getattr(serializer_field.parent, 'instance', None)
    def set_context(self, serializer):
          self.queryset = queryset
          self.fields = fields
          self.serializer_field = None
  
    def set_context(self, serializer):
    def set_context(self, serializer):
    def set_context(self, serializer):
          # Determine the existing instance, if this is an update operation.
          instance = getattr(serializer, 'instance', None)
  
          # Ensure uniqueness.
          filter_kwargs = dict([
keep keep keep keep replace replace replace keep keep keep keep keep
 First pass at unique_for_date, unique_for_month, unique_for_year 
rest_framework/validators.py