Loading sqlite function failed with runserver but works in django shell

[Tazo Gil]

Dear all

django 1.8
python 3.4

The sqlite function sqlite-Levenshtein (https://github.com/mateusza/SQLite-Levenshtein) is working perfectly in the django shell, example:

self.annotate(distance=Func(Value(aword), F('word'), function='levenshtein')).filter(distance__lte=settings.DISTANCE_LEVENSHTEIN).order_by("distance")

but not with runserver : "no such function: levenshtein"

I load this extension in my app __init__.py as follow:

from mezzanine.conf import settings
# levenshtein exists in postgresql, sqlite needs extension
if 'sqlite3' in settings.DATABASES['default']['ENGINE']:
    from django.db import connection
    cursor =connection.cursor()
    cursor.db.connection.enable_load_extension(True)
    cursor.db.connection.load_extension(settings.SQLITE_LEVENSHTEIN)

with settings.SQLITE_LEVENSHTEIN = ="/usr/local/src/sqlite-Levenshtein/src/.libs/liblevenshtein.so"

I certainly miss something, hope somebody will help me, thanks by advance.