def METHOD_NAME(self) -> None:
    classes = astroid.extract_node(
        """
    class class_a(object): #@
        pass
    class classb(object): #@
        pass
    class CLASSC(object): #@
        pass
    """
    )
    messages = [
        MessageTest(
            "invalid-name",
            node=classes[0],
            args=(
                "Class",
                "class_a",
                "'(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern",
            ),
            confidence=HIGH,
            line=2,
            col_offset=0,
            end_line=2,
            end_col_offset=13,
        ),
        MessageTest(
            "invalid-name",
            node=classes[2],
            args=(
                "Class",
                "CLASSC",
                "the `down` group in the '(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern",
            ),
            confidence=HIGH,
            line=6,
            col_offset=0,
            end_line=6,
            end_col_offset=12,
        ),
    ]
    with self.assertAddsMessages(*messages):
        cls = None
        for cls in classes:
            self.checker.visit_classdef(cls)
        if cls:
            self.checker.leave_module(cls.root)