class — Expert Examples

class ValidatedMeta(type):
    def __new__(mcs, name, bases, namespace):
        # Require all public methods to have docstrings
        for key, value in namespace.items():
            if callable(value) and not key.startswith("_"):
                if not getattr(value, "__doc__", None):
                    raise TypeError(
                        f"{name}.{key}() must have a docstring"
                    )
        return super().__new__(mcs, name, bases, namespace)

class API(metaclass=ValidatedMeta):
    def get_users(self):
        """Fetch all users."""
        return []

    def get_orders(self):
        """Fetch all orders."""
        return []

print(f"API created with metaclass: {type(API)}")
print(f"Methods: {[m for m in dir(API) if not m.startswith('_')]}")

try:
    class BadAPI(metaclass=ValidatedMeta):
        def no_docs(self):  # missing docstring
            pass
except TypeError as e:
    print(f"Metaclass rejected: {e}")