When using the csv.DictReader a dialect can be given to change the behavior of interpretation of the csv file.

The Dialect has an option "skipinitialspace" which shall ignore the whitespace after the delimiter according to the documentation (https://docs.python.org/3/library/csv.html).

Unfortunately this works only for spaces but not for tabs which are also whitespaces.

See the following code snippet applied on the attached file:

with open("conf-csv", "r") as csvfile:
    csv.register_dialect("comma_and_ws", skipinitialspace=True)
    csv_dict_reader = csv.DictReader(csvfile, dialect="comma_and_ws")
    for line in csv_dict_reader:
        print(line)

The second line shall not contain "\t" chars.

https://bugs.python.org/issue21297#msg216907 to be related and has a patch. It refers to whitespace as only space ('U+0020') with tabs being ignored.

Current code where only space is taken into account : https://github.com/python/cpython/blob/fd628cf5adaeee73eab579393cdff71c8f70cdf2/Modules/_csv.c#L621

Sorry, I overlooked the patch. The issue reported is the same in issue21297 but the patch was about changing whitespace to space in the doc instead of changing the behavior as I can see from the discussion.