          )
  
      # Methods for constructing serializer fields...
  
      def build_field(self, field_name, info, model, nested_depth):
          """
          Return a two tuple of (cls, kwargs) to build a serializer field with.
          """
          if field_name in info.fields_and_pk:
              return self.build_standard_field(field_name, info, model)
 
</s> remove             return self.build_standard_field(field_name, info, model)
 </s> add             model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field) </s> remove         ret.update(hidden_fields)
 </s> add         fields.update(hidden_fields) </s> remove         return ret
 </s> add         return fields </s> remove                 return self.build_relational_field(field_name, info, model)
 </s> add                 return self.build_relational_field(field_name, relation_info) </s> remove         return field_cls, kwargs
 </s> add         return field_class, field_kwargs
    def build_field(self, field_name, info, model_class, nested_depth):
          )
  
      # Methods for constructing serializer fields...
  
    def build_field(self, field_name, info, model_class, nested_depth):
          """
          Return a two tuple of (cls, kwargs) to build a serializer field with.
          """
          if field_name in info.fields_and_pk:
              return self.build_standard_field(field_name, info, model)
keep keep keep keep replace keep keep keep keep keep
 Final bits of docs for ModelSerializer fields API 
rest_framework/serializers.py