setting the time format for timezone offset in props

hi, I would like extract the timezone offset in time format in props. example time format , 2017-02-05T01:20:10.049-0500: 0.855: TIME_FORMAT = %Y-%m-%dT%H:%M:%S.%3N-%Z But the above timeformat which i defined is not working. I want my timestamp in splunk to have upto 2017-02-05T01:20:10.049-0500 ignoring 0.855