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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 iscsi_iqn():
    '''
    Return iSCSI IQN
    '''
    grains = {}
    grains['iscsi_iqn'] = False
    if salt.utils.platform.is_linux():
        grains['iscsi_iqn'] = _linux_iqn()
    elif salt.utils.platform.is_windows():
        grains['iscsi_iqn'] = _windows_iqn()
    elif salt.utils.platform.is_aix():
        grains['iscsi_iqn'] = _aix_iqn()
    return grains