olevba: error 'NoneType' object has no attribute 'splitlines'

[decalage2]

error triggered by olevba 0.56.1.dev1 on Win10 both with Python 3.8.3 or Python 2.7.14, with this sample:
https://labs.inquest.net/dfi/hash/2bfb95bc1e1ff7801796cfb8c1047feebfd8576b8496030cd559d5bac804c9bb
https://www.virustotal.com/gui/file/2bfb95bc1e1ff7801796cfb8c1047feebfd8576b8496030cd559d5bac804c9bb
From this tweet: https://mobile.twitter.com/JohnLaTwC/status/1312433855056416768

First we get this error:

ERROR    VBA code returned by extract_all_macros is not a string

Then this:

Traceback (most recent call last):
  File "\Users\u\dev\oletools\oletools\olevba.py", line 4032, in process_file
    vba_code_filtered = filter_vba(vba_code)
  File "\Users\u\dev\oletools\oletools\olevba.py", line 2136, in filter_vba
    vba_lines = vba_code.splitlines()
AttributeError: 'NoneType' object has no attribute 'splitlines'
ERROR    Error processing file 2bfb95bc1e1ff7801796cfb8c1047feebfd8576b8496030cd559d5bac804c9bb ('NoneType' object has no attribute 'splitlines')!

So somewhere a function returns None instead of a string for the VBA code.

Interestingly, if I scan it with olevba 0.55.2, I get a different error, and the analysis continues with an empty macro and just P-code:

ValueError: CompressedChunkSize != 4098 but CompressedChunkFlag == 0

[decalage2]

Note that oledump 0.0.54 is also unable to decompress the VBA code.

[decalage2]

In fact the relaxed mode was too relaxed, because no exception was raised when a VBA_Module object was not completely initialised due to a malformed compressed stream. In that case the VBA_Module.code_str was set to None, triggering the exception above.
Now VBA_Module.init raises the exception, and olevba can try other methods to get code to analyse (e.g. P-code).