def METHOD_NAME(src: str, dst: str, suffix: Any | None = None):
    """
    Implements a recursive copy function similar to Unix's "cp -r" command.
    Surprisingly, python does not have a real equivalent. shutil.copytree
    only works if the destination directory is not present.
    Args:
        src (str): Source folder to copy.
        dst (str): Destination folder.
        suffix: Suffix to be added for copied files.
    """
    abssrc = os.path.abspath(src)
    absdst = os.path.abspath(dst)
    try:
        os.makedirs(absdst)
    except OSError:
        # If absdst exists, an OSError is raised. We ignore this error.
        pass
    for f in os.listdir(abssrc):
        fpath = os.path.join(abssrc, f)
        if os.path.isfile(fpath):
            if suffix is not None:
                new_path = f"{fpath}_{suffix!s}"
                shutil.copy(fpath, new_path)
                fpath = new_path
            shutil.copy(fpath, absdst)
        elif not absdst.startswith(fpath):
            METHOD_NAME(fpath, os.path.join(absdst, f), suffix=suffix)
        else:
            warnings.warn(f"Cannot copy {fpath} to itself")