Generating one MD5/SHA1 checksum of multiple files in Python

I have looked through several topics about calculating checksums of files in Python but none of them answered the question about one sum from multiple files. I have several files in sub directories and would like to determine if there was any change in one or more of them. Is there a way to generate one sum from multiple files?

EDIT: This is the way I do it to get a list of sums:

checksums = [(fname, hashlib.md5(open(fname, 'rb').read()).digest()) for fname in flist]

Solution

So I made it :) This way one hash sum is generated for a file list.

hash_obj = hashlib.md5(open(flist[0], 'rb').read())
for fname in flist[1:]:
    hash_obj.update(open(fname, 'rb').read())
checksum = hash_obj.digest()

Thank you PM 2Ring for your input!

Note that md5 has been cracked so use it only for non security critical purposes.