timestamp - Python copy file but keep original

Python query.

I want to take a copy of a file, called randomfile.dat, and add a timestamp to the end of the copied file.

However, I want to keep the original file too. So in my current directory (no moving files) I would end up with:
randomfile.dat
randomfile.dat.201711241923 (or whatever the timestamp format is..)

Can someone advise? Anything I have tried causes me to lose the original file.

Answer

How about this?

$ ls

$ touch randomfile.dat

$ ls

randomfile.dat

$ python
[...]
>>> import time
>>> src_filename = 'randomfile.dat'
>>> dst_filename = src_filename + time.strftime('.%Y%m%d%H%M')

>>> import shutil
>>> shutil.copy(src_filename, dst_filename)

'randomfile.dat.201711241929'
>>> [Ctrl+D]

$ ls
randomfile.dat
randomfile.dat.201711241929