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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def discover_handler_classes(handlers_package):
 """ 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 """

    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