Как сделать правильно список из списков объектов? Не могу правильно код написать

import csv
class DuplicateData:
    def __init__(self):
        id = 0
        filename = ""
        path = ""
        filesize = 0
        group = 0
        pixels = 0
        collected = 0
filelog = open("c:\\filelog.txt","w+", encoding="cp1251")
duplicatefiles = []
groupduplicatefiles = []
id = 0
newgroup = 0
oldgroup = 0
with open("d:\\search.csv", newline='') as searchdata:
    reader = csv.reader(searchdata)
    has_header = csv.Sniffer().has_header(searchdata.read(1024))
    searchdata.seek(0)
    reader = csv.reader(searchdata)
    if has_header:
        next(reader)
    for row in reader:
        obj = DuplicateData()
        id += 1
        newgroup = int(row[8])
        if (newgroup != oldgroup and oldgroup != 0):
            groupduplicatefiles.append(duplicatefiles)
            duplicatefiles.clear()
        obj.id = id
        obj.filename = row[1]
        filelog.write(obj.filename + "\n")
        obj.path = row[2]
        obj.filesize = int(row[3])
        obj.group = int(row[8])
        obj.pixels = int(row[16]) * int(row[17])
        obj.collected = 0
        duplicatefiles.append(obj)
        oldgroup = newgroup
groupduplicatefiles.append(duplicatefiles)
for group in groupduplicatefiles:
    for file in group:
        print(file.filename)