from shlex import shlex

lexer = shlex("a \n b")
print ",".join(lexer)

lexer = shlex("a # comment \n b")
print ",".join(lexer)

lexer = shlex("a \n b")
lexer.whitespace=" "
print ",".join(lexer)

lexer = shlex("a # comment \n b")
lexer.whitespace=" "
print ",".join(lexer)