def install_hook():
 for hook in sys.meta_path:
  if isinstance(hook, XonshImportHook):
   break
 else:
  sys.meta_path.append(XonshImportHook())

def install_hook ( ) : for hook in sys . meta_path : if isinstance ( hook , XonshImportHook ) : break else : sys . meta_path . append ( XonshImportHook ( ) )
install xonsh import hook in sys .