Write a code that looks for a repeating student number and replaces it with "9090". lst = [ ["0001", "Antonov", "Anton", "Igorevich", "08/20/2009", "BST161"] ["1102", "Bogov", "Artem", "Igorevich", "25.01.2010", "BST162"] ["0333", "Glagoleva", "Anastasiya", "Nikolaevna", "11.07.2009", "BST163"] ["4004", "Stepanova", "Natalia", "Aleksandrovna", "13.02.2008", "BST161"] ["0045", "Bokov", "Igor", "Kharitonovich", "02.06.2009", "BST161"], ["0096", "Vasil'kov", "Valentin", "Sergeevich", "20.03.2009", "BST164"], ["0607", "Siropova", "Violetta", "Eduardovna", "28.05.2010", "BST162"], ["4004", "Potapov", "Dmitry", "Stanislavovich", "14.02.2012", "BST161"] ]

def find_duplicates(lst):
    new_lst = []
    for i in lst:
        if i[0] not in new_lst:
            new_lst.append(i[0])
        else:
            i[0] = "9090"
    return new_lst
     
find_duplicates(lst)