Environmental

Improvement:
- 3 Support pathlib
- 1 Include PEP 484 type annotations

Improvement:
- 2 Include the missing variable name in the AttributeError

Bugfix:
- Support setting a default value of a different type than what would be expected otherwise. This allows setting default to `None`.

First version.

Supports
- Booleans
- Complex
- Floats
- Integers
- Lists
- Sets
- Strings
- Tuples