NameError: File '_MAIN_0.toc' exists

[RoseOu]

Hello, I install Flask-WhooshAlchemy and config according to your QuickStart,
but when I use docker to deploy my app, run it and visit my route，it raise the error：

File "/usr/local/lib/python2.7/site-packages/whoosh/filedb/filestore.py", line 552, in rename_file
  raise NameError("File %r exists" % newname)
NameError: File '_MAIN_0.toc' exists

My code:

app/Init.py:

import flask_whooshalchemy as whooshalchemy

def create_app(config_name=None, main=True):
    if config_name is None:
        config_name = 'default'
    app = Flask(__name__)
    app.config.from_object(config[config_name])

    config[config_name].init_app(app)
    db.init_app(app)
    moment.init_app(app)
    toolbar.init_app(app)
    login_manager.init_app(app)

    from .models import BlogPost
    whooshalchemy.whoosh_index(app, BlogPost)

    return app

app = create_app(config_name = 'default')

app/models.py:

class BlogPost(db.Model):
    __tablename__ = 'blogpost'
    __searchable__ = ['title', 'content'] 

    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String)  
    content = app.db.Column(db.Text)  

config.py

class Config:
    WHOOSH_BASE = os.path.join(basedir,"whoosh_index")