def METHOD_NAME(self):
    '''
    Function for preliminary set-up to execute the test
    '''
    self.err_paths = []
    self.device_list = []
    smm = SoftwareManager()
    for pkg in ["lsscsi", "pciutils"]:
        if not smm.check_installed(pkg) and not smm.install(pkg):
            self.cancel("%s is not installed" % pkg)
    self.wwids = self.params.get('wwids', default='')
    self.pci_device = self.params.get("pci_devices", default='')
    self.count = int(self.params.get("count", default=1))
    system_pci_adress = pci.get_pci_addresses()
    system_wwids = multipath.get_multipath_wwids()
    if self.wwids:
        self.wwids = self.wwids.split(' ')
        for wwid in self.wwids:
            if wwid not in system_wwids:
                self.cancel("%s not present in the system", wwid)
            for path in multipath.get_paths(wwid):
                self.device_list.append(path)
    elif self.pci_device:
        self.pci_device = self.pci_device.split(' ')
        for pci_id in self.pci_device:
            if pci_id not in system_pci_adress:
                self.cancel("%s not present in the system", pci_id)
            cmd = "ls -l /dev/disk/by-path/"
            output = process.system_output(cmd).decode('utf-8')
            for line in output.splitlines():
                if pci_id in line and 'part' not in line:
                    self.device_list.append(line.split('/')[-1])
    else:
        self.cancel("please provide pci adrees or wwids of scsi disk")