wfdb.io._header.HeaderSyntaxError: invalid syntax in signal line

while I use wfdb to load mit-bih-polysomnographic-database-1.0.0

wfdb.rdrecord(libpath + filename)

libpath:'mit-bih-polysomnographic-database-1.0.0/'

filename:'slp01a'

but return wfdb.io._header.HeaderSyntaxError: invalid syntax in signal line

I don't know what happen, I found all exaples from git-hub just like this

How to load the datebase properly, thank's for you help.