how can I make this code without built in function sort sorted

Question

class KeyIndex:

    def __init__(self, a):

        self.k = a

    def search(self, val):

        for ele in self.k:

            if ele == val:

                return True

        else:

            return False

    def sort(self):

        return sorted(self.k)

if __name__ == '__main__':

    a = [51,32,9,14,17,4]

    i = KeyIndex(a)

    if i.search(5):

        print(True)

    else:

        print(False)

    if i.search(10):

        print(True)

    else:

        print(False)

    print(i.sort())