Graphene

import graphene

class MyType(graphene.ObjectType):
    my_field = graphene.String()

# settings.py
MIDDLEWARE = [
    # ... other Django middleware
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'graphql_jwt.middleware.JSONWebTokenMiddleware',
    # ...
]

GRAPHENE = {
    'SCHEMA': 'your_project.schema.schema',
    'MIDDLEWARES': [
        'graphql_jwt.middleware.JSONWebTokenMiddleware',
    ],
}

# Example of a resolver returning None incorrectly
# def resolve_my_field(root, info):
#     user = User.objects.filter(id=root.user_id).first() # if user is not found, it's None
#     return user.name # This would raise the error if user is None

# Corrected resolver
def resolve_my_field(root, info):
    user = User.objects.filter(id=root.user_id).first()
    if user:
        return user.name
    return None # Or raise a specific error/return a default value

pip install --upgrade graphene graphql-core
# If still problematic, try pinning graphql-core (e.g., for older Graphene versions)
# pip install graphene==2.1.8 graphql-core==2.3.2

# Wrong:
# from graphene import ObjectType
# class MyModelType(ObjectType):
#     class Meta:
#         model = MyModel

# Correct:
from graphene_django.types import DjangoObjectType

class MyModelType(DjangoObjectType):
    class Meta:
        model = MyModel