Add typehint for nsmclient.py to silence mypy

extras/pynsm/nsmclient.py

@@ -28,7 +28,7 @@ OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWA
 """
 
 import logging;
-logger = None #filled by init with prettyName
+logger: logging.Logger  #filled by init with client logger.
 
 import struct
 import socket