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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 exists(zpool):
    '''
    Check if a ZFS storage pool is active

    zpool : string
        Name of storage pool

    CLI Example:

    .. code-block:: bash

        salt '*' zpool.exists myzpool

    '''
    # list for zpool
    # NOTE: retcode > 0 if zpool does not exists
    res = __salt__['cmd.run_all'](
        __utils__['zfs.zpool_command'](
            command='list',
            target=zpool,
        ),
        python_shell=False,
        ignore_retcode=True,
    )

    return res['retcode'] == 0