pony.orm.core.BindingError: Database object was already bound to SQLite provider

[FedorAdo]

In the project, the files from the example

config.py

db_params = {
    'provider': 'sqlite',
    'filename': 'test.sqlite',
    'create_db': True
}

Traceback (most recent call last):
File "D:/DEV/code/serv_be/migrate.py", line 5, in
db.migrate()
File "d:\dev\code\serv_be.venv\src\pony\pony\orm\core.py", line 786, in migrate
self._bind(*args, **kwargs)
File "d:\dev\code\serv_be.venv\src\pony\pony\orm\core.py", line 800, in _bind
throw(BindingError, 'Database object was already bound to %s provider' % self.provider.dialect)
File "d:\dev\code\serv_be.venv\src\pony\pony\utils\utils.py", line 106, in throw
raise exc
pony.orm.core.BindingError: Database object was already bound to SQLite provider

Actually why?