diff --git a/Include/Python-ast.h b/Include/Python-ast.h
index 6eec6c3..53a6a4b 100644
--- a/Include/Python-ast.h
+++ b/Include/Python-ast.h
@@ -355,20 +355,9 @@
         asdl_seq *kw_defaults;
 };
 
-enum _arg_kind {SimpleArg_kind=1, NestedArgs_kind=2};
 struct _arg {
-        enum _arg_kind kind;
-        union {
-                struct {
-                        identifier arg;
-                        expr_ty annotation;
-                } SimpleArg;
-                
-                struct {
-                        asdl_seq *args;
-                } NestedArgs;
-                
-        } v;
+        identifier arg;
+        expr_ty annotation;
 };
 
 struct _keyword {
@@ -535,10 +524,8 @@
                            varargannotation, asdl_seq * kwonlyargs, identifier
                            kwarg, expr_ty kwargannotation, asdl_seq * defaults,
                            asdl_seq * kw_defaults, PyArena *arena);
-#define SimpleArg(a0, a1, a2) _Py_SimpleArg(a0, a1, a2)
-arg_ty _Py_SimpleArg(identifier arg, expr_ty annotation, PyArena *arena);
-#define NestedArgs(a0, a1) _Py_NestedArgs(a0, a1)
-arg_ty _Py_NestedArgs(asdl_seq * args, PyArena *arena);
+#define arg(a0, a1, a2) _Py_arg(a0, a1, a2)
+arg_ty _Py_arg(identifier arg, expr_ty annotation, PyArena *arena);
 #define keyword(a0, a1, a2) _Py_keyword(a0, a1, a2)
 keyword_ty _Py_keyword(identifier arg, expr_ty value, PyArena *arena);
 #define alias(a0, a1, a2) _Py_alias(a0, a1, a2)
diff --git a/Include/graminit.h b/Include/graminit.h
index 6e1d409..e3929db 100644
--- a/Include/graminit.h
+++ b/Include/graminit.h
@@ -6,79 +6,75 @@
 #define funcdef 261
 #define parameters 262
 #define typedargslist 263
-#define tname 264
-#define tfpdef 265
-#define tfplist 266
-#define varargslist 267
-#define vname 268
-#define vfpdef 269
-#define vfplist 270
-#define stmt 271
-#define simple_stmt 272
-#define small_stmt 273
-#define expr_stmt 274
-#define augassign 275
-#define del_stmt 276
-#define pass_stmt 277
-#define flow_stmt 278
-#define break_stmt 279
-#define continue_stmt 280
-#define return_stmt 281
-#define yield_stmt 282
-#define raise_stmt 283
-#define import_stmt 284
-#define import_name 285
-#define import_from 286
-#define import_as_name 287
-#define dotted_as_name 288
-#define import_as_names 289
-#define dotted_as_names 290
-#define dotted_name 291
-#define global_stmt 292
-#define nonlocal_stmt 293
-#define assert_stmt 294
-#define compound_stmt 295
-#define if_stmt 296
-#define while_stmt 297
-#define for_stmt 298
-#define try_stmt 299
-#define with_stmt 300
-#define with_var 301
-#define except_clause 302
-#define suite 303
-#define test 304
-#define test_nocond 305
-#define lambdef 306
-#define lambdef_nocond 307
-#define or_test 308
-#define and_test 309
-#define not_test 310
-#define comparison 311
-#define comp_op 312
-#define star_expr 313
-#define expr 314
-#define xor_expr 315
-#define and_expr 316
-#define shift_expr 317
-#define arith_expr 318
-#define term 319
-#define factor 320
-#define power 321
-#define atom 322
-#define testlist_comp 323
-#define trailer 324
-#define subscriptlist 325
-#define subscript 326
-#define sliceop 327
-#define exprlist 328
-#define testlist 329
-#define dictorsetmaker 330
-#define classdef 331
-#define arglist 332
-#define argument 333
-#define comp_iter 334
-#define comp_for 335
-#define comp_if 336
-#define testlist1 337
-#define encoding_decl 338
-#define yield_expr 339
+#define tfpdef 264
+#define varargslist 265
+#define vfpdef 266
+#define stmt 267
+#define simple_stmt 268
+#define small_stmt 269
+#define expr_stmt 270
+#define augassign 271
+#define del_stmt 272
+#define pass_stmt 273
+#define flow_stmt 274
+#define break_stmt 275
+#define continue_stmt 276
+#define return_stmt 277
+#define yield_stmt 278
+#define raise_stmt 279
+#define import_stmt 280
+#define import_name 281
+#define import_from 282
+#define import_as_name 283
+#define dotted_as_name 284
+#define import_as_names 285
+#define dotted_as_names 286
+#define dotted_name 287
+#define global_stmt 288
+#define nonlocal_stmt 289
+#define assert_stmt 290
+#define compound_stmt 291
+#define if_stmt 292
+#define while_stmt 293
+#define for_stmt 294
+#define try_stmt 295
+#define with_stmt 296
+#define with_var 297
+#define except_clause 298
+#define suite 299
+#define test 300
+#define test_nocond 301
+#define lambdef 302
+#define lambdef_nocond 303
+#define or_test 304
+#define and_test 305
+#define not_test 306
+#define comparison 307
+#define comp_op 308
+#define star_expr 309
+#define expr 310
+#define xor_expr 311
+#define and_expr 312
+#define shift_expr 313
+#define arith_expr 314
+#define term 315
+#define factor 316
+#define power 317
+#define atom 318
+#define testlist_comp 319
+#define trailer 320
+#define subscriptlist 321
+#define subscript 322
+#define sliceop 323
+#define exprlist 324
+#define testlist 325
+#define dictorsetmaker 326
+#define classdef 327
+#define arglist 328
+#define argument 329
+#define comp_iter 330
+#define comp_for 331
+#define comp_if 332
+#define testlist1 333
+#define encoding_decl 334
+#define yield_expr 335