TypeError: init_s3_keys() takes exactly 1 argument (0 given)

I am looking for using briefly to build my pipelined workflow.
When I try to import briefly, this error occurs:
```
briefly/build/lib.linux-x86_64-2.7/briefly/__init__.py in ()
19
20 from properties import *
---> 21 from wrappers import *
22 from core import *

briefly/build/lib.linux-x86_64-2.7/briefly/wrappers.py in ()
15 #
16
---> 17 import process
18 import hadoop
19 import java

briefly/build/lib.linux-x86_64-2.7/briefly/process.py in ()
18 import sys
19 import hashlib
---> 20 import fs
21
22 from node import *
briefly/build/lib.linux-x86_64-2.7/briefly/fs.py in ()
28
29 # Initialize keys first.
---> 30 S3Handler.init_s3_keys()
31
32 # Shared filesystem/s3 utilities.

TypeError: init_s3_keys() takes exactly 1 argument (0 given)
```

I have s4cmd 2.0.1 installed.

Thanks,

Lei

Start in briefly/fs.py at the module-level S3Handler.init_s3_keys() call shown in the traceback, then inspect the S3Handler definition and how s4cmd 2.0.1 is supported. Reproduce the import failure and verify that importing briefly completes without the TypeError.

Written by the indexing model from the issue text.