Throws error on str.join(str, Generator[pyobj])

The code:

from python import re
regexPattern = '|'.join(map(re.escape, delimiters))

which was inspired by:
https://stackoverflow.com/questions/4998629/split-string-with-multiple-delimiters-in-python

and which works fine in Python (using 'import re' rather than "from python import re'),
in Codon throws an error:
error: 'str' object has no method 'join' with arguments (str, Generator[pyobj])