'Verify if device exists.
Check if a device mac exists and matches the given VF pci slot
@param device_mac: device mac
@param pci_slot: VF address'

def device_exists(self, device_mac, pci_slot):

    embedded_switch = self._get_emb_eswitch(device_mac, pci_slot)
    if embedded_switch:
        return True
    return False
