Improve Error Message if error object is not type of DjangoObjectType

[bastiW]

See also: https://stackoverflow.com/a/49834443/2440049

If you inherit from a wrong type then the error you get an error which is confusing.
Currently you get ...type object ‘User’ has no attribute ‘name’
now you get ** [object_name] must inherit from DjangoObjectType. **

        if "has no attribute 'name'" in str(e):
            object_name = str(e).split("'")[1]

Those two lines I don't like so much but I didn't know how to get something like an error id.

Actually the current confusing part of the error is raised by Django. Do you think it is a better Idea to create a pull request in the django repository?

[coveralls]

Coverage decreased (-0.3%) to 94.268% when pulling 9b53db4 on bastiW:master into f76f38e on graphql-python:master.

[coveralls]

Coverage decreased (-0.3%) to 94.268% when pulling 9b53db4 on bastiW:master into f76f38e on graphql-python:master.

[bastiW]

Is it already solved in a better way?