chunk size in python large size

1def rows(f, chunksize=1024, sep='|'):
2    """
3    Read a file where the row separator is '|' lazily.
4
5    Usage:
6
7    >>> with open('big.csv') as f:
8    >>>     for r in rows(f):
9    >>>         process(r)
10    """
11    row = ''
12    while (chunk := f.read(chunksize)) != '':   # End of file
13        while (i := chunk.find(sep)) != -1:     # No separator found
14            yield row + chunk[:i]
15            chunk = chunk[i+1:]
16            row = ''
17        row += chunk
18    yield row
19