Add sample

sample.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+
+import keyring
+from libpyvivotek import VivotekCamera
+
+cam = VivotekCamera(host='192.168.2.184', port=80, usr='root',
+                    pwd=keyring.get_password('camera', 'root'),
+                    sec_lvl="admin")
+
+print(f"Camera model:  {cam.model_name}")
+print(f"Firmware:      {cam.get_param('system_info_firmwareversion')}")
+print(f"Network info:  {cam.get_param('status_eth_i0')}")
+print(f"RTSP port:     {cam.get_param('network_rtsp_port')}")
+print(f"Serial number: {cam.get_serial()}")
+print(f"MAC address:   {cam.get_mac()}")
+print(f"Date & time:   {cam.get_param('system_date')} {cam.get_param('system_time')}")
+print(f"Status:        {cam.get_param('status_vi_i0')}")