import re


def verify_mac(mac: str) -> bool:
    """
    Verify if mac address is correctly formed.

    :param mac: Mac address to verify.
    :return: True is correctly formed, False if not.
    """
    return bool(re.match(r'^([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}$', mac))