def inst_typedef(instruction):
    if instruction[0] == '*':
        return None
    elif instruction[0] == 's':
        return Ins.InitialInstruction(instruction[0], instruction[4])
    elif instruction[2] == ' ':
        return Ins.WriteInstruction(instruction[0], instruction[4], instruction[6:-1])
    else:
        return Ins.ReadInstruction(instruction[0], instruction[4], instruction[2])