From e33a6002bfcf411210f52d5a1bce6c3919da1bce Mon Sep 17 00:00:00 2001
From: B4rtware <34386047+B4rtware@users.noreply.github.com>
Date: Wed, 8 Jan 2020 13:35:38 +0100
Subject: [PATCH] fix datetime type does get converted to a string

to_representation will convert the datetime field into a string representation. However the to_representation on the method field will only call its underlying method.
---
 graphene_django/rest_framework/mutation.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/graphene_django/rest_framework/mutation.py b/graphene_django/rest_framework/mutation.py
index 3009c06..f9b074d 100644
--- a/graphene_django/rest_framework/mutation.py
+++ b/graphene_django/rest_framework/mutation.py
@@ -137,5 +137,13 @@ class SerializerMutation(ClientIDMutation):
     @classmethod
     def perform_mutate(cls, serializer, info):
         obj = serializer.save()
-        kwargs = serializer.to_representation(obj)
+        
+        kwargs = {}
+        for f, field in serializer.fields.items():
+            if not field.write_only:
+                if isinstance(field, serializers.SerializerMethodField):
+                    kwargs[f] = field.to_representation(obj)
+                else:
+                    kwargs[f] = field.get_attribute(obj)
+                    
         return cls(errors=None, **kwargs)