List extend vs concat

from time import time
from random import randint


class ExtendVsConcat:

    def __init__(self):
        self.add_to_me = []
        self.concat_times = []
        self.extend_times = []

    def main_tester(self):
        for i in range(1000000):
            rand_list = []
            for _ in range(randint(1, 10)):
                rand_list.append(randint(1, 50))

            start_time = time()
            self.add_to_me += rand_list
            diff_time = time() - start_time
            self.concat_times.append(diff_time)
            self.add_to_me.clear()

            start_time = time()
            self.add_to_me.extend(rand_list)
            diff_time = time() - start_time
            self.extend_times.append(diff_time)
            self.add_to_me.clear()

        average_concat = sum(self.concat_times) / len(self.concat_times)
        average_extend = sum(self.extend_times) / len(self.extend_times)
        print(f"Concat average: {average_concat}")
        print(f"Extend average: {average_extend}")


test = ExtendVsConcat()
test.main_tester()