$ python2
Python 2.7.15 (default, May 16 2018, 17:50:09) 
[GCC 8.1.1 20180502 (Red Hat 8.1.1-1)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import json
>>> from base64 import b64encode
>>> b64encode(json.dumps("{}").encode())
'Int9Ig=='
>>> 
$ python3
Python 3.6.5 (default, Mar 29 2018, 18:20:46) 
[GCC 8.0.1 20180317 (Red Hat 8.0.1-0.19)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import json
>>> from base64 import b64encode
>>> b64encode(json.dumps("{}").encode())
b'Int9Ig=='
>>> 
$