FileNotFoundError: [Errno 2]在python中没有这样的文件或目录:'classA'，尽管该文件已经制作完成

sav = []
def fileKeep(sav):
    classA = open("classA", "r")
    for line in classA:
        sav.append(line.split())
    file.close()
    return
fileKeep(sav)
sav = []
def fileKeep(sav):
    classA = open("