if?isinstance(max_features,?int):
????count?=?sorted(list(count.items()),?key=lambda?x:x[1])
????if?max_features?is?not?None?and?len(count)?>?max_features:
????????count?=?count[-int(max_features):]
????for?w,?_?in?count:
????????self.dict[w]?=?len(self.dict)
else:
????for?w?in?sorted(count.keys()):
????????self.dict[w]?=?len(self.dict)
????????
?求這段代碼的理解