AttributeError: 'NoneType' object has no attribute 'total_changes'

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/dist-packages/discord/client.py", line 343, in _run_event
    await coro(*args, **kwargs)
  File "/home/tf2maps/bot_zeus/cogs/tags.py", line 27, in on_message
    tag = await Tag.filter(key=key)
  File "/usr/local/lib/python3.7/dist-packages/tortoise/queryset.py", line 842, in _execute
    ).execute_select(self.query, custom_fields=list(self._annotations.keys()))
  File "/usr/local/lib/python3.7/dist-packages/tortoise/backends/base/executor.py", line 124, in execute_select
    _, raw_results = await self.db.execute_query(query.get_sql())
  File "/usr/local/lib/python3.7/dist-packages/tortoise/backends/sqlite/client.py", line 29, in translate_exceptions_
    return await func(self, query, *args)
  File "/usr/local/lib/python3.7/dist-packages/tortoise/backends/sqlite/client.py", line 133, in execute_query
    start = connection.total_changes
AttributeError: 'NoneType' object has no attribute 'total_changes'

Summary
I believe that there is an issue with the Tortoise.init finding and creating the database connection

There is code calling the init function from main.py, and the model in question is used later in a plugin under cogs/tags.py

The code below is just snippets for the sake of brevity.
If there is some way I can confirm that the connection is not active by getting a property on the Tag object
Or it would be nice if I could explictly tell the init function to initalize models that i have directly imported instead of passing a string to it.

Folder structure:

├── main.py
├── tags.sqlite
├── cogs/
│   ├── __init__.py
│   ├── tags.py
├── models/
│   ├── __init__.py
│   └── Tag.py

Main.py

...
await Tortoise.init(
    db_url="sqlite://tags.sqlite",
    modules={'models': ["models.Tag"]}
)
...

cogs/tags.py

...
async def on_message(self, message):
    key = message.content.lower()
    tag = await Tag.filter(key=key)
    await message.channel.send(tag.value)
...

models/Tag.py

from tortoise import Tortoise, fields
from tortoise.models import Model

class Tag(Model):
    id = fields.IntField(pk=True)
    key = fields.TextField()
    value = fields.CharField(max_length=1024)
    author = fields.CharField(max_length=128)
    date = fields.DatetimeField(null=True)

Start with the Tortoise.init call in main.py and the Tag.filter use in cogs/tags.py, then trace the SQLite connection handling in tortoise/backends/sqlite/client.py where total_changes is accessed. Reproduce the example and confirm the initialization order and connection state; done means Tag.filter no longer reaches this AttributeError and the expected initialization behavior is clear.