Keywords
Python has the following keywords or reserved words; they cannot be used as identifiers.
andasassertbreakclasscontinuedefdelelifelseexceptexec(changed to a built-in function in 3.x)False(added in 3.x)finallyforfromglobalifimportinislambdaNone(added in 3.x)nonlocal(added in 3.x)notorpassprint(changed to a built-in function in 3.x)raisereturnTrue(added in 3.x)trywhilewithyield
As exec and print are functions as of Python 3 they are not reserved words anymore.
Read more about this topic: Python Syntax And Semantics