The below "test.code1" is not base64 encoded. Though, it is a good file.

t:~$ python3 -m base64 -d test.code1
Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/lib/python3.6/base64.py", line 602, in <module>
    main()
  File "/usr/lib/python3.6/base64.py", line 586, in main
    func(f, sys.stdout.buffer)
  File "/usr/lib/python3.6/base64.py", line 512, in decode
    s = binascii.a2b_base64(line)
binascii.Error: Incorrect padding