2.3.1 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:

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 Python 2.6, the identifier as will become a keyword.

Changed in version 2.4: None became a constant and is now recognized by the compiler as a name for the builtin object None. Although it is not a keyword, you cannot assign a different object to it.

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