def _percent_match(date_classes, tokens):
match_count = [<NUM_LIT:0>] * len(date_classes)<EOL>for i, date_class in enumerate(date_classes):<EOL><INDENT>for token in tokens:<EOL><INDENT>if date_class.is_match(token):<EOL><INDENT>match_count[i] += <NUM_LIT:1><EOL><DEDENT><DEDENT><DEDENT>percentages = tuple([float(m) / len(tokens) for m in match_count])<EOL>return percentages<EOL>
For each date class, return the percentage of tokens that the class matched (floating point [0.0 - 1.0]). The
returned value is a tuple of length patterns. Tokens should be a list.