include them using \verbatiminput.  This has the advantage that pages
can still break at reasonable places, and examples that go longer than
a page won't get cut off.

Make a few small markup adjustments for consistency.

Explain that PyObject_New() is not a C function but a polymorphic
beast that returns a pointer to the type that's passed as the first
arg.

Explain why type objects use the PyObject_VAR_HEAD.