funcdef: 'def' NAME parameters ':' suite
parameters: '(' [varargslist] ')'
-varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' '*' '*' NAME] | '*' '*' NAME) | fpdef ['=' test] (',' fpdef ['=' test])* [',']
+varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' ('**'|'*' '*') NAME] | ('**'|'*' '*') NAME) | fpdef ['=' test] (',' fpdef ['=' test])* [',']
fpdef: NAME | '(' fplist ')'
fplist: fpdef (',' fpdef)* [',']
shift_expr: arith_expr (('<<'|'>>') arith_expr)*
arith_expr: term (('+'|'-') term)*
term: factor (('*'|'/'|'%') factor)*
-factor: ('+'|'-'|'~') factor | atom trailer*
+factor: ('+'|'-'|'~') factor | power
+power: atom trailer* ('**' factor)*
atom: '(' [testlist] ')' | '[' [testlist] ']' | '{' [dictmaker] '}' | '`' testlist '`' | NAME | NUMBER | STRING+
lambdef: 'lambda' [varargslist] ':' test
trailer: '(' [arglist] ')' | '[' subscript ']' | '.' NAME
-subscript: test | [test] ':' [test]
+subscript: test (',' test)* [','] | [test] ':' [test]
exprlist: expr (',' expr)* [',']
testlist: test (',' test)* [',']
dictmaker: test ':' test (',' test ':' test)* [',']