can't index old data

[maryam-hesham]

i tried index_all(app)
but i have this error
for model, _ in whoosh_index_all(app):
File "C:\Python27\lib\site-packages\flask_whooshalchemyplus.py", line 372, in whoosh_index_all
'sqlalchemy'].db.Model._decl_class_registry.values()
KeyError: 'sqlalchemy'