I've used any because it needs to be infinitely recursive, something
that we simply can't model. But basically until it goes into validator
we have no way of knowing what's going on, since one can write code
like:
```python
KwargInfo[str]('arg', object, validator=_some_very_complex_logic_to_get_specific_string)
```
As such, we can't assume that validator is receiving a type _T, it could
be anything.
We have a lot of these. Some of them are harmless, if unidiomatic, such
as `if (condition)`, others are potentially dangerous `assert(...)`, as
`assert(condtion)` works as expected, but `assert(condition, message)`
will result in an assertion that never triggers, as what you're actually
asserting is `bool(tuple[2])`, which will always be true.
Because currently you can write something like:
```python
KwargInfo('capture', bool)
```
Which proclaims "this must be bool", but the default is then not valid.
Because of the convertor function we have no guarantee that what we're
getting is in fact a `Dict[str, TYPE_var]`, it might well be anything in
the values, so we need to do some casting and set the return type to
object. This works out fine in practice as our declared `TypeDict`
inputs in the actual function signatures will be used instead.
This commit introduces a new type of `HoldableObject`: The
`SecondLevelHolder`. The primary purpose of this class is
to handle cases where two (or more) `HoldableObject`s are
stored at the same time (with one default object). The
best (and currently only) example here is the `BothLibraries`
class.
This allows checking specific values that are added or deprecated, which
we do a surprising amount of. This works with both containers and scalar
values
Dylan Baker
Daniel Mensinger
Xavier Claessens