2.3.1 关键字 Keywords

The following identifiers are used as reserved words, or keywords of the language, and cannot be used as ordinary identifiers. They must be spelled exactly as written here:

以下标识符用作保留字, 或者叫做语言的关键字, 并且不能作为普通标识符使用, 而且它们必须像下面的那样严格拼写.

and       del       for       is        raise    
assert    elif      from      lambda    return   
break     else      global    not       try      
class     except    if        or        while    
continue  exec      import    pass      yield    
def       finally   in        print

Note that although the identifier as can be used as part of the syntax of import statements, it is not currently a reserved word.

In some future version of Python, the identifiers as and None will both become keywords.