import re


def device_name_convention(host):
    """
    Helper filter function to filter hosts based targeting
    host names which a specified naming convention

    Examples:
        - lab-junos-08.tst.dfjt.local
        - lab-arista-22.prd.dfjt.local
        - lab-nxos-01.lab.dfjt.local

    :param host: The host you want to filter on

    :return bool: True if it matches, False if it doesn't match
    """
    # Perform regex match on host name and return boolean
    if re.match("\w{3}\-\w+\-\d{2}.\w{3}.dfjt.local", host.name):
        return True
    else:
        return False