Refer to Extending and Embedding the Python Interpreter,
section 1.12, ``Providing a C API for an Extension Module,'' for more
information on using these objects.
This subtype of PyObject represents an opaque value, useful
for C extension modules who need to pass an opaque value (as a
void* pointer) through Python code to other C code. It is
often used to make a C function pointer defined in one module
available to other modules, so the regular import mechanism can be
used to access C APIs defined in dynamically loaded modules.
Creates a PyCObject from the void *cobj. The
destr function will be called when the object is reclaimed.
The desc argument can be used to pass extra callback data for
the destructor function.
