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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def remove_service(service, zone=None, permanent=True):
    '''
    Remove a service from zone. This option can be specified multiple times.
    If zone is omitted, default zone will be used.

    CLI Example:

    .. code-block:: bash

        salt '*' firewalld.remove_service ssh

    To remove a service from a specific zone

    .. code-block:: bash

        salt '*' firewalld.remove_service ssh dmz
    '''
    if zone:
        cmd = '--zone={0} --remove-service={1}'.format(zone, service)
    else:
        cmd = '--remove-service={0}'.format(service)

    if permanent:
        cmd += ' --permanent'

    return __firewall_cmd(cmd)