docs: def import_modules_from_package(package):
      """Import modules from package and append into sys.modules
  
      :param package: full package name, e.g. east.asts
      """
      path = [os.path.dirname(__file__), '..'] + package.split('.')
      path = os.path.join(*path)
      for root, dirs, files in os.walk(path):
          for filename in files:
              if filename.startswith('__') or not filename.endswith('.py'):
                  continue
              new_package = ".".join(root.split(os.sep)).split("....")[1]
              module_name = '%s.%s' % (new_package, filename[:-3])
              if module_name not in sys.modules:
                  __import__(module_name)