code: def find_package_dirs(root_path):
      
      package_sdirs = set()
      for entry in os.listdir(root_path):
          fname = entry if root_path == '.' else pjoin(root_path, entry)
          if isdir(fname) and exists(pjoin(fname, '__init__.py')):
              package_sdirs.add(fname)
      return package_sdirs
docs: Find python package directories in directory `root_path`
  
      Parameters
      ----------
      root_path : str
          Directory to search for package subdirectories
  
      Returns
      -------
      package_sdirs : set
          Set of strings where each is a subdirectory of `root_path`, containing
          an ``__init__.py`` file.  Paths prefixed by `root_path`