p |OP* |append_elem |I32 optype|OP* head|OP* tail
p |OP* |append_list |I32 optype|LISTOP* first|LISTOP* last
p |I32 |apply |I32 type|SV** mark|SV** sp
+Afp |void |apply_attrs_string|char *stashpv|CV *cv|char *attrstr|STRLEN len
Ap |SV* |avhv_delete_ent|AV *ar|SV* keysv|I32 flags|U32 hash
Ap |bool |avhv_exists_ent|AV *ar|SV* keysv|U32 hash
Ap |SV** |avhv_fetch_ent |AV *ar|SV* keysv|I32 lval|U32 hash