Python—对目录中的所有文件执行比较函数

我有一个函数可以找到字符串的平均长度

 def mean_length(sequence):
    sum = 0.0
    nonblank = 0
    for string in sequence:
        if string.strip():
            sum = sum + len(string)
            nonblank = nonblank + 1
    return sum/nonblank

我在创建一个新函数时遇到了麻烦，该函数将在一个目录中查找.txt文件，与所有其他.txt文件相比，该目录的平均字符串长度最高。任何帮助都会很好，特别是如何比较目录中的所有文件。谢谢

path = # This will be the path to the directory from your current working driectory

import glob
files = glob.glob(path + '*.txt') # This returns a list containing all files that are in the path that end in ".txt"
for file in files:
    # Do what you need to do here for each file