问ascii编解码器无法解码

EN

Traceback (most recent call last):
  File "/Users/Name/Desktop/TCSS 142/Project 2/project2.py", line 17, in <module>
for line in file:
  File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/encodings/ascii.py", line 26, in decode
   return codecs.ascii_decode(input, self.errors)[0]
UnicodeDecodeError: 'ascii' codec can't decode byte 0x92 in position 3: ordinal not in range(128)

import glob

# Returns a list of all filenames ending in .txt
# precondition: none
# postcondition: a list of all filenames in the current directory
#                with a .txt extension
def getFilesInDir():
    filenames = glob.glob('./*.txt')
    for i in range(len(filenames)):
        filenames[i] = filenames[i][2:]
    return filenames

files = getFilesInDir()

for el in files:
    file = open(el, 'r')
    for line in file:
        print(line)
    file.close()