Sounds like you're trying to find how much time is between two points. You should use datetime
objects for this (and in general in Python!)
import datetime
import time
before = datetime.datetime.now() # don't convert to string!
time.sleep(5) # do some stuff....
after = datetime.datetime.now()
delta = after - before
# delta is a datetime.timedelta object.
print(delta)
# which by default stringifies to %H:%M:%S.%f
In my test case (manually writing everything to a repr) I got
Python 3.5.0 (v3.5.0:374f501f4567, Sep 13 2015, 02:16:59) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import datetime
>>> before = datetime.datetime.now()
>>> after = datetime.datetime.now()
>>> delta = after - before
>>> print(delta)
0:00:05.239524