SystemError: Negative size passed to PyString_FromStringAndSize

[kartrocket]

Bot the commands:

1. dex -f /XXX/XXX/mongodb/var/log/mongodb/mongod.log mongodb://root:XXXXXXXXXXXXXX@XXX.XXX.XXX.XXX:27017/databaseName

2. dex -f /mnt/pb1d1p1/mongodb/var/log/mongodb/mongod.log

yield:

Traceback (most recent call last):
File "/usr/local/bin/dex", line 233, in
main(sys.argv[1:])
File "/usr/local/bin/dex", line 218, in main
return md.analyze_logfile(options.logfile_path)
File "/usr/local/lib/python2.7/dist-packages/dex/dex.py", line 212, in analyze_logfile
self.analyze_logfile_object(file)
File "/usr/local/lib/python2.7/dist-packages/dex/dex.py", line 230, in analyze_logfile_object
for line in file_object:
SystemError: Negative size passed to PyString_FromStringAndSize

How do I fix this?