diff --git a/Grammar/Grammar b/Grammar/Grammar
index f1b5117e91c..3d957a79940 100644
--- a/Grammar/Grammar
+++ b/Grammar/Grammar
@@ -23,7 +23,7 @@ eval_input: testlist NEWLINE* ENDMARKER
 
 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)* [',']
 
@@ -70,11 +70,12 @@ and_expr: shift_expr ('&' shift_expr)*
 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)* [',']