import os, fnmatch, re
dir_source = os.curdir
masks = ["*.txt", "*.log"]
def find_file_for_masks(root, masks):
    root = os.path.abspath(root)
    parrent = re.compile("|".join(map(fnmatch.translate, masks)), re.I).match
    for path, dirs, files in os.walk(root):
        for name in filter(parrent, files):
            filename = os.path.join(path, name)
            print(filename)
find_file_for_masks(dir_source, masks)

def PathFind(pattr, root="."):
    u"""аналог find из bash"""
    for di, dl, fl in os.walk(root):
        for f in glob.fnmatch.filter(fl, pattr):
            yield os.path.join(di, f)
t_old=0
found = None
for name in PathFind("*.txt"):
    t = os.stat(name).st_mtime
    if t > t_old:
        found=name
        t_old=t

>>> import os
>>> import glob
>>> 
>>> d = {f: os.stat(f).st_mtime for f in glob.iglob('*.txt')}
>>> max(d, key=lambda i: d[i])
'vi_help.txt'
>>>

>>> d = {'a': 123, 'b': 456}
>>> max(d, key=lambda i: d[i])
'b'
>>>

def listFiles(files, masks):
    findFiles = []
    parrent = re.compile("|".join(map(fnmatch.translate, masks)), re.I).match
    for filename in filter(parrenr, files):
        d = {filename: int((ftp.sendcmd(`MDTM ` + files))[4:])}
        findFiles.append(max(d, key=lambda i: d[i]))
    return findFiles

masks = ["*.txt", "*.log"]
def listFiles(files, masks):
    findFiles = []
    parrent = re.compile("|".join(map(fnmatch.translate, masks)), re.I).match
    d = {filename: ((ftp.sendcmd('MDTM ' + filename))[4:]) for filename in filter(parrent, files)}
    findFiles.append(max(d, key=lambda i: d[i]))
    return findFiles

def listFiles(files, masks):
    findFiles = []
    for x in masks:
        parrent = re.compile(fnmatch.translate(x)).match
        d = {filename: ((ftp.sendcmd('MDTM ' + filename))[4:]) for filename in filter(parrent, files)}
        print d
        findFiles.append(max(d, key=lambda i: d[i]))
    return findFiles