      The default ValidationError behavior is to stringify each item in the list
      if the messages are a list of error messages.
  
      In the case of nested serializers, where the parent has many children,
      then the child's `serializer.errors` will be a list of dicts.
  
      We need to override the default behavior to get properly nested error dicts.
      """
  
      def __init__(self, message):
 
</s> remove         self.messages = message
 </s> add         if isinstance(message, dict):
            self.messages = [message]
        else:
            self.messages = message </s> remove                 self.object = serializer.object
                into[self.source or field_name] = serializer.object
 </s> add                 if isinstance(serializer, ModelSerializer):
                    into[self.source or field_name] = serializer
                else:
                    into[self.source or field_name] = serializer.object </s> remove         if self.parent.object:
            # Set the serializer object if it exists
            obj = getattr(self.parent.object, field_name)
            self.object = obj
 </s> add         # Set the serializer object if it exists
        obj = getattr(self.parent.object, field_name) if self.parent.object else None </s> remove     def save_object(self, obj):
 </s> add     def save_object(self, obj, parent=None, fk_field=None):
    then the child's `serializer.errors` will be a list of dicts.  In the case
    of a single child, the `serializer.errors` will be a dict.
      The default ValidationError behavior is to stringify each item in the list
      if the messages are a list of error messages.
  
      In the case of nested serializers, where the parent has many children,
    then the child's `serializer.errors` will be a list of dicts.  In the case
    of a single child, the `serializer.errors` will be a dict.
  
      We need to override the default behavior to get properly nested error dicts.
      """
  
      def __init__(self, message):
keep keep keep keep replace keep keep keep keep keep
 One-to-one writable, nested serializer support 
rest_framework/serializers.py