Unhandled Exception: 'NoneType' object has no attribute 'select'

[regulatre]

Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 801, in __bootstrap_inner
  File "/usr/lib/python2.7/threading.py", line 754, in run
  File "433mobile.py", line 213, in gpsThread
  File "433mobile.py", line 236, in gpsConnectAndMonitor
  File "/root/.local/lib/python2.7/site-packages/gps3/gps3.py", line 116, in next
<type 'exceptions.AttributeError'>: 'NoneType' object has no attribute 'select'

Unclear what conditions led to the situation. The application works fine normally.