I os.set_inheritable(fdDupSTDOUT) if fdDupSTDOUT is not None

Not if it evaluates to True. If for some crazy reason fdDupSTDOUT==0, I'll still
try to use it

Author: dkogan

gnuplotlib.py

@@ -1502,7 +1502,7 @@ def _startgnuplot(self):
         # would happen by default, but in python3 I need to do this extra thing
         # for some reason. And it's a new thing that didn't exist in python2, so
         # I need to explicitly allow this to fail in python2
-        if self.fdDupSTDOUT:
+        if self.fdDupSTDOUT is not None:
             try:
                 os.set_inheritable(self.fdDupSTDOUT, True)
             except AttributeError: