[Fixed]-Ldapdb: "'NoneType' object is not callable" when adding ldap database to django

Update:

The django-ldapdb version has to be at least 0.9.

pip install django-ldapdb>=0.9

Old post:

django-ldapdb supports at the moment only the Django version’s 1.8-1.10.

So the solution is realy simple:

pip install Django==1.10