Serhiy Storchaka added the comment: These opcodes are always used with CALL_FUNCTION_EX (which can be used also without any of them). f(*a, *b, **c, **d) 1 0 LOAD_NAME 0 (f) 2 LOAD_NAME 1 (a) 4 LOAD_NAME 2 (b) 6 BUILD_TUPLE_UNPACK_WITH_CALL 2 8 LOAD_NAME 3 (c) 10 LOAD_NAME 4 (d) 12 BUILD_MAP_UNPACK_WITH_CALL 2 14 CALL_FUNCTION_EX 1 I though about naming CALL_FUNCTION_EX as CALL_FUNCTION_VAR in 3.6, but this name was used in pre-3.6 bytecode with different semantic. Now I think there is smaller change of confusion, so it can be renamed to CALL_FUNCTION_VAR or something other. ---------- _______________________________________ Python tracker https://bugs.python.org/issue30076 _______________________________________