In the 'Terminology' section of the optparse module documentation, under
the description of the term 'required option', a reference to example
implementations of this concept are stated to be available in two
example files of the source distribution:

"See examples/required_1.py and examples/required_2.py in the optparse
source distribution for two ways to implement required options with
optparse."

These two files do not appear to have ever been available with python 
but are found in the original 'Optik' distribution that this module is
derived from.  I am guessing that this is a result of the documentation
being copied when the module was added to the standard library as it
also appears in the Optik documentation almost verbatim:
http://optik.sourceforge.net/doc/1.5/tao.html

Suggest the reference to these files:
1) Be removed as to prevent confusion as to their existence/location
2) Be updated to point to the Optik source on source forge
3) Merge the examples in line with the documentation
or
4) Some other option I have not thought of

Patch which removes reference to example_1.py and example_2.py

Patch which references the original optik module when referring to
example required option modules.

Patch takes the contents of required_1.py from the optik source adds it
in the optparse documentation as well as removing references to the two
files.

Thanks for the report. I removed the references in r77092.