Completed 6.7-codecs. This one is a bit odd as it deals with inputs, so it needs to have in input of another file piped in, and takes two arguments 1) an encoding, and 2) a error_handling method name.  I have been running tests with this command - 'python 6.6-mmap.py | python 6.7-codecs.py utf-16 ignore' but there are lots of possible options.
Completed 6.8-stringIO
Completed 6.9-fnmatch
Completed 6.10-dircache
Completed 6.11-filecmp, and that's also the end of Chapter 6 The File System.  I am excited to get started on Chapter 7 Data Persistence and Exchange