missing argument in lilypond/python/convertrules.py:5702

[Martin Tarenskeen via bug-lilypond]

Hi,

when trying convert-ly from lilypond 2.27.3 I bumped into an error 
message pointing to

lilypond/python/convertrules.py:5702 so I look it up and it seems to be 
missing an argument:

@rule((2, 27, 3), "ly:book? -> ly:book-or-bookpart?")
def conv(s):
   s = re.sub(r'ly:book\?',r'ly:book-or-bookpart?')
   return s

I think this should be:

@rule((2, 27, 3), "ly:book? -> ly:book-or-bookpart?")
def conv(s):
   s = re.sub(r'ly:book\?',r'ly:book-or-bookpart?', s)
   return s

At least it fixed the error message for me, but maybe someone can look 
into it.

Martin