标识符修复中的字符无效？

Question

file = open(filename, 'r')
file.read()
new = 'first_filter_' + filename
words.save(new)
#words = text.split(' ')

错误消息：

UnicodeDecodeError: 'ascii' codec can't decode byte 0xc2 in position 24: ordinal not in range(128)