如何让Spacy正确标记化am/pm表达式？

from spacy.tokenizer import Tokenizer
from spacy.util import compile_prefix_regex, compile_infix_regex, compile_suffix_regex

def custom_tokenizer(nlp):
    prefix_re = compile_prefix_regex(nlp.Defaults.prefixes)
    suffix_re = compile_suffix_regex(nlp.Defaults.suffixes)
    infix_re = compile_infix_regex(nlp.Defaults.infixes + [r"\b\d{1,2}(?:am|pm)\b"])

    return Tokenizer(nlp.vocab, prefix_search=prefix_re.search,
                     suffix_search=suffix_re.search, infix_finditer=infix_re.finditer,
                     token_match=None)

nlp.tokenizer = custom_tokenizer(nlp)