def environ_add_path(env, key, path):
 old = env.get(key)
 if old:
  env[key] = ((path + ':') + old)
 else:
  env[key] = path

def environ_add_path ( env , key , path ) : old = env . get ( key ) if old : env [ key ] = ( ( path + ':' ) + old ) else : env [ key ] = path
add path to path link environments .