class FieldMutation(graphene.Mutation):
    class Arguments:
        id = graphene.String(required=True)
        name = graphene.String()
        acres = graphene.Int()
    field = graphene.Field(FieldType)

    def mutate(self, info, **kwargs):
        field = Field.objects.get(pk=kwargs.get("id"))
        field.name = kwargs.get("name", field.name)
        field.acres = kwargs.get("acres", field.acres)
        field.save()
        return FieldMutation(field=field)


class Mutation:
    update_field = FieldMutation.Field()


schema = graphene.Schema(query=Query, mutation=Mutation)