      def clean_fields(self, data):
          """
          Run validate_<fieldname> methods on the serializer
          """
          fields = self.get_fields(serialize=False, data=data, nested=self.opts.nested)
  
          for field_name, field in fields.items():
              try:
                  clean_method = getattr(self, 'validate_%s' % field_name, None)
                  if clean_method:
 
</s> remove     def clean_fields(self, data):
 </s> add     def validate_fields(self, attrs): </s> remove                     data = clean_method(data, source)
 </s> add                     attrs = clean_method(attrs, source) </s> remove     def clean_all(self, attrs):
 </s> add     def validate_all(self, attrs): </s> remove         return data
 </s> add         return attrs </s> remove             self._errors['non_field_errors'] = 'No input provided'
 </s> add             self._errors['non_field_errors'] = ['No input provided']
        fields = self.get_fields(serialize=False, data=attrs, nested=self.opts.nested)
      def clean_fields(self, data):
          """
          Run validate_<fieldname> methods on the serializer
          """
        fields = self.get_fields(serialize=False, data=attrs, nested=self.opts.nested)
  
          for field_name, field in fields.items():
              try:
                  clean_method = getattr(self, 'validate_%s' % field_name, None)
                  if clean_method:
keep keep keep keep replace keep keep keep keep keep
 Clean up internal names and documentation 
rest_framework/serializers.py