The ability to specify the default is very useful in datetutil.parser.parse. Would you be interested in allowing the same argument for the more strict dateutil.parser.isoparse?

The following is current behavior on the reduced precision ISO 8601 string "2024-04" and its US equivalent "April 2024".

from datetime import datetime
from dateutil.parser import isoparse, parse

isoparse("2024-04")  # datetime.datetime(2024, 4, 1, 0, 0)
parse("April 2024")  # datetime.datetime(2024, 4, 26, 0, 0)
parse("April 2024", default=datetime.max)  # datetime.datetime(2024, 4, 30, 23, 59, 59, 999999)

What I'm needing to do is parse only ISO 8601 strings while having the option to "round up" (in addition to the "round down" approach of the current version). The enhancement would allow something like the following:

isoparse("2024-04", default=datetime.max)  # datetime.datetime(2024, 4, 30, 23, 59, 59, 999999)