I was getting the same error.
I found the following bug report for parsedatetime library which seems to be the culprit here: https://bugs.launchpad.net/ubuntu/+source/parsedatetime/+bug/1302963
Removing the ubuntu installed python-parsedatetime and using the pip version (1.4) of that library resolved this issue for me.
I was getting the same error.
I found the following bug report for parsedatetime library which seems to be the culprit here: https:/ /bugs.launchpad .net/ubuntu/ +source/ parsedatetime/ +bug/1302963
Removing the ubuntu installed python- parsedatetime and using the pip version (1.4) of that library resolved this issue for me.