code: def discover_handler_classes(handlers_package):
      
      if handlers_package is None:
          return
  
      # Add working directory into PYTHONPATH to import developer packages
      sys.path.insert(0, os.getcwd())
  
      package = import_module(handlers_package)
  
      # Continue searching for module if package is not a module
      if hasattr(package, '__path__'):
          for _, modname, _ in pkgutil.iter_modules(package.__path__):
              import_module('{package}.{module}'.format(package=package.__name__, module=modname))
  
      return registered_handlers
docs: Looks for handler classes within handler path module.
  
      Currently it's not looking deep into nested module.
  
      :param handlers_package: module path to handlers
      :type handlers_package: string
      :return: list of handler classes