Split CSV file into multiple files sorted my colum

Hi im a Python noob and i want to make a programm to split my csv file into multiple csv files

the file looks something like this:

main.csv

Name;Lieferung;Name;Ort;Postleitzahl
somename;60072470;somename;someadress;83620
somename;60071938;somename;someadress;48691
somename;60072194;somename;someadress;13595
somename;60072194;somename;someadress;13595
somename;60072511;somename;someadress;82140

and i want the code to automaticly create multiple csv files grouped by Lieferung:

60072470.csv

somename;60072470;somename;someadress;83620

60071938.csv

somename;60071938;somename;someadress;48691

60072194.csv

somename;60072194;somename;someadress;13595
somename;60072194;somename;someadress;13595

60072511.csv

somename;60072511;somename;someadress;82140

Can someone help me, i did a lot o reaserch but i cant make it 🙁

THX a Lot

>Solution :

import csv

data = {}

with open("a.csv", newline='') as file:
    reader = csv.reader(file, delimiter=';')
    header = next(reader)
    for row in reader:
        data.setdefault(row[1], [])
        data[row[1]].append(row)

for name, row in data.items():
    with open(f"{name}.csv", "w", newline='') as file:
        writer = csv.writer(file, delimiter=';')
        writer.writerow(header)
        writer.writerows(row)