Avoid calling __init__ for classmethod/staticmethod

[saluto]

Suppose we want a CLI that is similar to git in the sense that we must first call init before interacting with the repo. For this, we aim for the following (simplified/partially implemented) class, which is intentionally similar to GitPythons Repo class (see here):

from pathlib import Path
import fire

class SomethingLikeGit:

  dirname = ".something_like_git"

  @classmethod
  def init(cls, path=None):
    path = Path(path or Path.cwd())
    path = path / cls.dirname
    print("Initializing at", path)
    path.mkdir()
    ...
    print("Done.")

  def __init__(self, path=None):
    path = Path(path or Path.cwd())
    for parent in (path, *path.parents):
      self.path = parent / self.dirname
      if self.path.exists():
        break
    else:
      raise FileNotFoundError(path)

  ...

if __name__ == "__main__":
  fire.Fire(SomethingLikeGit)

When we run the command python something_like_git.py init, it first tries to instantiate the class via __init__, which fails (FileNotFoundError) since it must first create the directory via init.
I think it makes generally more sense if Fire would call classmethods/staticmethods directly on the class without trying to instantiate it. This is usually also how class/static methods are used in a programmatic way (e.g. for git.Repo).

Note that the fix for #113 does not resolve this issue. This is because the path argument for __init__ is (intentionally) optional, so Fire thinks it can call __init__ first. If path wasn't optional, it would behave as wanted: init would be called without first calling __init__.

Anyway, thanks for your great work!