10.7 append mode, **10.2** `open()`, **10.1** read mode, **10.1** `read()`, **10.1** `readline()`, **10.1** `readlines()`, **10.1** write mode, **10.2** `write()`, **10.2** `writelines()`, **10.2** `filter()`, 17.5, A.11 `finally` clause, **11.2**, 11.3 `float` type, **3.3**, 3.5 floating-point prec