diff --git a/src/ethereum_test_vm/opcode.py b/src/ethereum_test_vm/opcode.py
index 398a7ae62c..90e10e0394 100644
--- a/src/ethereum_test_vm/opcode.py
+++ b/src/ethereum_test_vm/opcode.py
@@ -33,7 +33,7 @@ def _get_int_size(n: int) -> int:
 
 
 def _stack_argument_to_bytecode(
-    arg: "int | bytes | str | Opcode | Bytecode | Iterable[int]",
+    arg: "int | bytes | SupportsBytes | str | Opcode | Bytecode | Iterable[int]",
 ) -> Bytecode:
     """
     Converts a stack argument in an opcode or macro to bytecode.