code: def hlp_source_under(folder):
      
      # walk the folder and find the __init__.py entries for packages.
      packages = []
      package_dir = dict()
      for root, dirs, files in os.walk(folder):
          for file in files:
              if file != '__init__.py':
                  continue
              full = os.path.dirname(os.path.join(root, file))
              relative = os.path.relpath(full, folder)
              packages.append(relative)
              package_dir[relative] = full
      # we use pprint because we want the order to always remain the same
      return 'packages={0},\npackage_dir={1}'.format(sorted(packages), pprint.pformat(package_dir))
docs: this function finds all the python packages under a folder and
      write the 'packages' and 'package_dir' entries for a python setup.py
      script