Would you be open to a PR that catches multiple errors and prints them all at once?

I was thinking that instead of the raise AttributeError(), the errors could be collected and then raised at the end

https://github.com/mortymacs/abcmeta/blob/4fef29bdc78b52830b9431d93f66cdccee1adf9b/abcmeta/init.py#L157-L187

Could be modified like this:

errors = []
for name, obj in vars(cls.__base__).items():
    ...
    if name not in cls.__dict__:
        errors.append(
            "Derived class '{}' has not implemented '{}' method of the"
            " parent class '{}'.".format(
                cls.__name__, name, cls.__base__.__name__
            )
        )
        continue
    ...
if errors:
    raise AttributeError("\n\n".join(errors))

Fixes #4

Adds feature and tests for printing multiple errors are once

> python tests/multiple_incorrect_methods_test.py
Traceback (most recent call last):
  File "/Users/kyleking/Developer/Pull_Requests/abcmeta/tests/multiple_incorrect_methods_test.py", line 27, in <module>
    class ABCDerived(ABCParent):
  File "/Users/kyleking/.asdf/installs/python/3.10.5/lib/python3.10/abc.py", line 106, in __new__
    cls = super().__new__(mcls, name, bases, namespace, **kwargs)
  File "/Users/kyleking/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/abcmeta/__init__.py", line 192, in __init_subclass__
    raise AttributeError("\n\n".join(errors))
AttributeError: Derived class 'ABCDerived' has not implemented 'method_1' method of the parent class 'ABCParent'.

Signature of the derived method is not the same as parent class:
- method_2(self, name: str, age: int) -> Dict[str, str]
?                      ^ -

+ method_2(self, name: int, age: int) -> Dict[str, str]
?                      ^^

Derived method expected to get 'name:<class 'str'>' paramter's type, but gets 'name:<class 'int'>'

Signature of the derived method is not the same as parent class:
- method_4(self, name: str, age: int) -> Tuple[str, str]
?                ^  ^

+ method_4(self, family: str, age: int) -> Tuple[str, str]
?                ^  ^^^

Derived method expected to get 'name' paramter, but gets 'family'

Only downside is that maybe the join on 2x \n could be more clear. Should it be something involving dashes like '-' * 80 or 3x \n?

Testing out a possible fix for CI. Worked locally in zsh. ~~Probably needed to make the step a bash shell~~ (already bash by default), but trying moving them to environment variables first

Update: ended up restoring the original text that worked before. Can't have nice things