[python3] ImportError: No module named 'cStringIO'

[Erich E. Hoover]

Line 46 of pkg_resources.py currently reads:
except NameError:
However, it should read:
except (ImportError, NameError):

Since if basestring is defined then the check will cause the error "ImportError: No module named 'cStringIO'". This issue can be reproduced with the following minimal script:
#!/usr/bin/python3

import pyqtgraph
import pkg_resources