that are currently reserved (and hence off-limits for names of your ownin python table - python reserved words false class finally is return none continue for lambda try true def from nonlocal while and del global not with as elif if or yield assert else import pass break except in raise table - is specific to python in python xthe set of reserved words differs slightlyprint is reserved wordbecause printing is statementnot built-in function (more on this later in this exec is reserved wordbecause it is statementnot built-in function nonlocal is not reserved word because this statement is not available in older pythons the story is also more or less the samewith few variationswith and as were not reserved until when context managers were officially enabled yield was not reserved until python when generator functions came online yield morphed from statement to expression in but it' still reserved wordnot built-in function as you can seemost of python' reserved words are all lowercase they are also all truly reserved--unlike names in the built-in scope that you will meet in the next part of this bookyou cannot redefine reserved words by assignment ( and results in syntax error besides being of mixed casethe first three entries in table - truefalseand noneare somewhat unusual in meaning--they also appear in the built-in scope of python described in and they are technically names assigned to objects in they are truly reserved in all other sensesthoughand cannot be used for any other purpose in your script other than that of the objects they represent all the other reserved words are hardwired into python' syntax and can appear only in the specific contexts for which they are intended in standard cpythonat least alternative implementations of python might allow user-defined variable names to be the same as python reserved words see for an overview of alternative implementationssuch as jython assignment statements