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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 resolve_address(address=None, vsys=None):
    '''
    Resolve address to ip address.
    Required version 7.0.0 or greater.

    address
        Address name you want to resolve.

    vsys
        The vsys name.

    CLI Example:

    .. code-block:: bash

        salt '*' panos.resolve_address foo.bar.com
        salt '*' panos.resolve_address foo.bar.com vsys=2

    '''
    _required_version = '7.0.0'
    if not __proxy__['panos.is_required_version'](_required_version):
        return False, 'The panos device requires version {0} or greater for this command.'.format(_required_version)

    if not address:
        raise CommandExecutionError("FQDN to resolve must be provided as address.")

    if not vsys:
        query = {'type': 'op',
                 'cmd': '<request><resolve><address>{0}</address></resolve></request>'.format(address)}
    else:
        query = {'type': 'op',
                 'cmd': '<request><resolve><vsys>{0}</vsys><address>{1}</address></resolve>'
                        '</request>'.format(vsys, address)}

    return __proxy__['panos.call'](query)