CLN: helper attribute to check for ArrayManager

[jorisvandenbossche]

xref #41878 (comment)

[jbrockmendel]

grepping for hasattr.*blocks shows a few more places this can be used

[jreback]

https://github.com/pandas-dev/pandas/runs/4364239489?check_suite_focus=true some typing :-<

[jorisvandenbossche]

Any suggestion how to deal with this? Because if mypy doesn't understand the helper function, that basically means that you need to add a cast (or ignore comment) every time this is used ..

[jbrockmendel]

Any suggestion how to deal with this? Because if mypy doesn't understand the helper function, that basically means that you need to add a cast (or ignore comment) every time this is used ..

1. type: ignore
2. add a blocks property to AM that raises NotImplementedError
3. ping @simonjayhawkins

[github-actions]

This pull request is stale because it has been open for thirty days with no activity. Please update and respond to this comment if you're still interested in working on this.

[simonjayhawkins]

I assume would need to make DataFrame Generic and add the _mgr class as a type parameter. Since _mgr is private, not sure it this would be best practice from a typing perspective as the DataFrame typing is public.

https://mypy.readthedocs.io/en/stable/generics.html#generics

[simonjayhawkins]

Thanks for the pull request, but it appears to have gone stale. If interested in continuing, please merge in the main branch, address any review comments and/or failing tests, and we can reopen.