Correct way to change bytes in a file?

[wavic]

Well, you have a choice what data type to use. 

data_set = {'one', 'two'}
data_list = ['one', 'two']
data_tuple = ('one', 'two')
data_string = "one,two" #csv style

All of this holds the same data and they are iterable.

In [16]: print("set: {}\nlist: {}\ntuple: {}\nstring: {}".format(
    ...:                       sys.getsizeof(data_set), 
    ...:                       sys.getsizeof(data_list), 
    ...:                       sys.getsizeof(data_tuple),
    ...:                       sys.getsizeof(data_string)))

Output:
set: 224
list: 80
tuple: 64
string: 56