Text tokenization approach

[satyrmipt]

Please explain why code

kwp=KeywordProcessor()
kwp.add_keywords_from_list(['111 ', '(2)'])
print(kwp.get_all_keywords())

aa=' 111  (2) '
print(kwp.extract_keywords(aa))

returns [' 111 ', '(2)']

and almost the same code with '111 ' instead of '111' in kw list (extra space at the end):

kwp=KeywordProcessor()
kwp.add_keywords_from_list(['111 ', '(2)'])
print(kwp.get_all_keywords())

aa=' 111 (2) '
print(kwp.extract_keywords(aa))

returns only one keyword ['111 ']

Obviously '(2)' is still in keyword list and in string to search in but it was not found by the second snippet.
My guess is you use some kind of tokenization and i would like to synchronize token pattern between fasttext and my custom procedure which generates key words set.