This example tests renaming the generated SWIG pure Python module to __init__.py

to turn the module into a Python package.

Use 'python runme.py' to run the test.

Overview:

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SWIG generates a pure Python module foo.py from the input interface file foo.i.

The foo.py file is generated within the pkg1 directory and is then renamed __init__.py.

This results in everything in the SWIG generated module being available in the Python

pkg1 package.

This approach of turning the SWIG generated module into a package worked in versions

of SWIG up to swig-3.0.8, but stopped working from swig-3.0.9 until it was

re-instated in swig-4.0.0. However, Python 2.7 or 3.3 and later are needed to

work out of the box. Python 3.2 does not work as this version of Python does

not set __package__ in __init__.py.