              # Ensure queryset is re-evaluated whenever used.
              queryset = queryset.all()
          return queryset
  
      def get_iterable(self, instance, source):
          relationship = get_attribute(instance, [source])
          return relationship.all() if (hasattr(relationship, 'all')) else relationship
  
      @property
      def choices(self):
          return dict([
 
</s> remove         relationship = super(PrimaryKeyRelatedField, self).get_iterable(instance, source)
 </s> add         relationship = super(PrimaryKeyRelatedField, self).get_iterable(instance, source_attrs) </s> remove     def get_iterable(self, instance, source):
 </s> add     def get_iterable(self, instance, source_attrs): </s> remove             return get_attribute(instance, [self.source])
 </s> add             return get_attribute(instance, self.source_attrs) </s> remove             return PKOnlyObject(pk=instance.serializable_value(self.source))
 </s> add             instance = get_attribute(instance, self.source_attrs[:-1])
            return PKOnlyObject(pk=instance.serializable_value(self.source_attrs[-1])) </s> remove         return self.child_relation.get_iterable(instance, self.source)
 </s> add         return self.child_relation.get_iterable(instance, self.source_attrs)
    def get_iterable(self, instance, source_attrs):
        relationship = get_attribute(instance, source_attrs)
              # Ensure queryset is re-evaluated whenever used.
              queryset = queryset.all()
          return queryset
  
    def get_iterable(self, instance, source_attrs):
        relationship = get_attribute(instance, source_attrs)
    def get_iterable(self, instance, source_attrs):
        relationship = get_attribute(instance, source_attrs)
          return relationship.all() if (hasattr(relationship, 'all')) else relationship
  
      @property
      def choices(self):
          return dict([
keep keep keep keep replace replace keep keep keep keep keep
 Support dotted source on relational fields 
rest_framework/relations.py