r the modules present below this entry or package on PYTHONPATH.

        For modules which are not packages, this will yield nothing.

        For packages and path entries, this will only yield modules one level
        down; i.e. if there is a package a.b.c, iterModules on a will only
        return a.b.  If you want to descend deeply, use walkModules.

        @return: a generator which yields PythonModule instances that describe
        modules which can be, or have been, imported.
        Nr