This is a coding specification started with PEP 328. When not adding parentheses, you need to add a backslash at the end of the line when breaking the line, as shown below:

from xxx import aaa, bbb, \
    ccc

Or write each line againfrom xxx import yyy:

from xxx import aaa
from xxx import bbb
from xxx import ccc

With parentheses, you can wrap new lines at will inside the parentheses:

from xxx import (
    aaa,
    bbb,
    ccc,
)

See PEP328

Personal understanding:

from django.core.exceptions import (
DisallowedHost, ImproperlyConfigured, RequestDataTooBig
)

Equivalent

from django.core.exceptions import DisallowedHost;
from django.core.exceptions import ImproperlyConfigured;
from django.core.exceptions import RequestDataTooBig;

The syntax looks simpler, and you can tell at a glance which methods are imported from a module. It's also a matter of habit. The benevolent sees benevolence and the wise see wisdom. Personally, it’s OK if it’s comfortable