          if isinstance(data, type('')) or isinstance(data, collections.Mapping) 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.run_validation(item) for item in data]
  
      def to_representation(self, data):
          """
          List of object instances -> List of dicts of primitive datatypes.
          """
 
</s> remove         return {
            six.text_type(key): self.child.run_validation(value)
            for key, value in data.items()
        }
 </s> add         return self.run_child_validation(data) </s> remove         ({'a': 1, 'b': None}, ['This field may not be null.']),
 </s> add         ({'a': 1, 'b': None, 'c': None}, {'b': ['This field may not be null.'], 'c': ['This field may not be null.']}), </s> remove     Values for `ListField` with CharField as child.
 </s> add     Values for `DictField` with CharField as child.
        return self.run_child_validation(data)
          if isinstance(data, type('')) or isinstance(data, collections.Mapping) 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.run_child_validation(data)
  
      def to_representation(self, data):
          """
          List of object instances -> List of dicts of primitive datatypes.
          """
keep keep keep keep replace keep keep keep keep keep
 Improve composite field child errors (#5655)

* Fixup DictField test descriptions

* Nest ListField/DictField errors under the idx/key

* Add nested ListField/DictField tests 
rest_framework/fields.py