# What this PR does
Remove
[`apps.get_model`](https://docs.djangoproject.com/en/3.2/ref/applications/#django.apps.apps.get_model)
invocations and use inline `import` statements in places where models
are imported within functions/methods to avoid circular imports.
I believe `import` statements are more appropriate for most use cases as
they allow for better static code analysis & formatting, and solve the
issue of circular imports without being unnecessarily dynamic as
`apps.get_model`. With `import` statements, it's possible to:
- Jump to model definitions in most IDEs
- Automatically sort inline imports with `isort`
- Find import errors faster/easier (most IDEs highlight broken imports)
- Have more consistency across regular & inline imports when importing
models
This PR also adds a flake8 rule to ban imports of `django.apps.apps`, so
it's harder to use `apps.get_model` by mistake (it's possible to ignore
this rule by using `# noqa: I251`). The rule is not enforced on
directories with migration files, because `apps.get_model` is often used
to get a historical state of a model, which is useful when writing
migrations ([see this SO answer for more
details](https://stackoverflow.com/a/37769213)). So `apps.get_model` is
considered OK in migrations (even necessary in some cases).
## Checklist
- [x] Unit, integration, and e2e (if applicable) tests updated
- [x] Documentation added (or `pr:no public docs` PR label added if not
required)
- [x] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not
required)
Added integration with [zvonok.com](https://zvonok.com) service.
Features:
- Phone number validation
- Test calls
- Selection of pre-recorded audio
- Making calls
- Processing call status
- Acknowledgment alert group (optional)
To process the call status, it is required to add a postback with the
GET method on the side of the zvonok.com service with the following
format ([more info
here](https://zvonok.com/ru-ru/guide/guide_postback/)):
```${ONCALL_BASE_URL}/zvonok/call_status_events?campaign_id={ct_campaign_id}&call_id={ct_call_id}&status={ct_status}&user_choice={ct_user_choice}```
The names of the transmitted parameters can be redefined through environment variables.
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Co-authored-by: Innokentii Konstantinov <innokenty.konstantinov@grafana.com>
