TypeError: cannot use a string pattern on a bytes-like object

Python version 3.7.7
flanker version 0.9.11

from flanker.addresslib import address                                                                                                                                                                                           

address.validate_address(<custom domaian email address>)  

----> 1 address.validate_address('custom domaian email address')

~/.virtualenvs/newvenv/lib/python3.7/site-packages/flanker/utils.py in wrapper(*args, **kwargs)
     62         @wraps(f)
     63         def wrapper(*args, **kwargs):
---> 64             return_value = f(*args, **kwargs)
     65             if 'metrics' in kwargs and kwargs['metrics'] == True:
     66                 #return all values

~/.virtualenvs/newvenv/lib/python3.7/site-packages/flanker/addresslib/address.py in validate_address(addr_spec, metrics, skip_remote_checks)
    321     # lookup custom local-part grammar if it exists
    322     bstart = time()
--> 323     plugin = plugin_for_esp(exchanger)
    324     mtimes['custom_grammar'] = time() - bstart
    325     if plugin and plugin.validate(paddr) is False:

~/.virtualenvs/newvenv/lib/python3.7/site-packages/flanker/addresslib/validate.py in plugin_for_esp(mail_exchanger)
    127     """
    128     for grammar in _CUSTOM_GRAMMAR_LIST:
--> 129         if grammar[0].match(mail_exchanger):
    130             return grammar[1]
    131 

TypeError: cannot use a string pattern on a bytes-like object

I found the fix
flanker/flanker/addresslib/address.py line 322

from
plugin = plugin_for_esp(exchanger)

to
plugin = plugin_for_esp(exchanger.decode('utf-8'))

Reproduce the failure with address.validate_address and inspect addresslib/address.py around line 322, then follow plugin_for_esp in addresslib/validate.py to understand the expected input type. Done means the reported custom-domain validation no longer raises the bytes/string TypeError and existing behavior remains intact.