yourstring = """"ABC", "XYZ,MNO", "KLM"
"ABC", "MN"
"ABC", "123", "10", "OPPA GANGNAM STYLE", "LADY\""""
import csv
import io


class MyDialect(csv.Dialect):
    strict = True
skipinitialspace = True
quoting = csv.QUOTE_ALL
delimiter = ','
quotechar = '"'
lineterminator = '\n'
b = io.StringIO(yourstring)
r = csv.reader(b, MyDialect())
for i in r:
    pass
Python – как читать/разбирать csv как строку?