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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 pair(address, key):
    '''
    Pair the bluetooth adapter with a device

    CLI Example:

    .. code-block:: bash

        salt '*' bluetooth.pair DE:AD:BE:EF:CA:FE 1234

    Where DE:AD:BE:EF:CA:FE is the address of the device to pair with, and 1234
    is the passphrase.

    TODO: This function is currently broken, as the bluez-simple-agent program
    no longer ships with BlueZ >= 5.0. It needs to be refactored.
    '''
    if not salt.utils.validate.net.mac(address):
        raise CommandExecutionError(
            'Invalid BD address passed to bluetooth.pair'
        )

    try:
        int(key)
    except Exception:
        raise CommandExecutionError(
            'bluetooth.pair requires a numerical key to be used'
        )

    addy = address_()
    cmd = 'echo {0} | bluez-simple-agent {1} {2}'.format(
        _cmd_quote(addy['device']), _cmd_quote(address), _cmd_quote(key)
    )
    out = __salt__['cmd.run'](cmd, python_shell=True).splitlines()
    return out