Make a howard decorator

[nhumrich]

Could have a class decorator that adds the fromdict and todict methods to the class as classmethods.

example:

@howard.howard
@dataclass
class Person:
    name: str
    age: int

my_dict = {'name': 'Bob', 'age': 24}
person = Person.fromdict(my_dict)

[iddan]

I think you better be off with inheriting a class because as of now you can't tell mypy that a decorator adds method to the class it's applied to.

[Ogaday]

I'd love a Howard decorator, but the mypy thing does look awkward. References:

• Allow adding attributes to classes after definition python/mypy#5363
• How to typecheck methods and attributes generated by metaprogramming python/mypy#1310
• https://mypy.readthedocs.io/en/stable/supported_python_features.html
• https://github.com/python/mypy/wiki/Unsupported-Python-Features