Fails on *+*

Hello!

Streamparser always fails while trying to parse this output of apertium's tagger:
'^*+*/*+*$'

Original string is '*+*'.

Traceback (most recent call last):
File "apertium2fastmorph.py", line 137, in parse_apertium
pos = mainpos(r)
File "streamparser/streamparser.py", line 90, in mainpos
return reading[-1].tags[0] # type: ignore
IndexError: list index out of range

I parsed the entire corpus consisting of hundreds of millions tokens, and this is the only part where it fails. If I change *+* to +* or *+ or ** or *** it works.

It seems that it is a bug.