def METHOD_NAME(extra: str) -> str:
    """Normalize extra name according to PEP 685
    >>> safe_extra("_FrIeNdLy-._.-bArD")
    'friendly-bard'
    >>> safe_extra("FrIeNdLy-._.-bArD__._-")
    'friendly-bard'
    """
    return _NON_ALPHANUMERIC.sub("-", extra).strip("-").lower()