ribotish tisdiff error?ZeroDivisionError: integer division or modulo by zero

[etmorefish]

hi,when I use the ribotish tisdiff ,some error information as follows: my command : ribotish tisdiff -1 pred1.txt -2 pred2.txt -a v1.sort.bam -b vi2.sort.bam -g test.gtf -o diff -v error informations:

Loading 2 TIS data... 1 TISs in pred1.txt. 1 TISs in pred2.txt. 1 TISs in total. Reading bams... JN Estimate scale factor... Traceback (most recent call last): File "/usr/bin/ribotish", line 4, in import('pkg_resources').run_script('ribotish==0.2.6', 'ribotish') File "/usr/lib/python2.7/site-packages/pkg_resources/init.py", line 654, in run_script self.require(requires)[0].run_script(script_name, ns) File "/usr/lib/python2.7/site-packages/pkg_resources/init.py", line 1441, in run_script exec(script_code, namespace, namespace) File "/usr/lib/python2.7/site-packages/ribotish-0.2.6-py2.7.egg/EGG-INFO/scripts/ribotish", line 56, in

File "/usr/lib/python2.7/site-packages/ribotish-0.2.6-py2.7.egg/EGG-INFO/scripts/ribotish", line 34, in main

File "build/bdist.linux-x86_64/egg/ribotish/run/tisdiff.py", line 254, in run File "build/bdist.linux-x86_64/egg/ribotish/zbio/exp.py", line 207, in TMM ZeroDivisionError: integer division or modulo by zero