def METHOD_NAME(
    callee_bytecode: bytes,
    initial_memory_length: int,
    opcode: Op,
) -> bytes:
    """
    Initial memory for the test.
    """
    assert len(callee_bytecode) <= initial_memory_length
    ret = bytes(list(islice(cycle(range(0x01, 0x100)), initial_memory_length)))
    if opcode in [Op.CREATE, Op.CREATE2]:
        # We also need to put the callee_bytecode as initcode in memory for create operations
        ret = callee_bytecode + ret[len(callee_bytecode) :]
    assert len(ret) == initial_memory_length
    return ret