Python Linter doesn't recognize that invalid data is being passed to a function

I have a function defined like so:

```
def verify_dataframe_info(vars, name: str, capsys, hasInfo: bool):
```

And I had code like so:

```
verify_dataframe_info(vars, 'se', capsys, true)
```

The 'true' value should be 'True'

Linter didn't recognize this mistake.
