‘Netstring.py’ is a Python module to encode / decode netstrings. A netstring is a simple protocol for encoding arbitrary strings in a file or datastream. They have the major advantage over the traditional zero terminated strings in that the reader knows the size of the string up front and does not have to examine the data a byte at the time.
There is no documentation for this module other than the docstrings, but hopefuly that should cover it. For more information on the netstring protocol see the official netstring protocol document.