Write a function to convert a date of yyyy-mm-dd format to dd-mm-yyyy format by using regex.
import re
def change_date_format(dt):
        return re.sub(r'(\d{4})-(\d{1,2})-(\d{1,2})', '\\3-\\2-\\1', dt)
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to convert a date of yyyy-mm-dd format to dd-mm-yyyy format by using regex.
import re
def change_date_format(dt):
        return re.sub(r'(\d{4})-(\d{1,2})-(\d{1,2})', '\\3-\\2-\\1', dt)[/INST]assert change_date_format("2026-01-02") == '02-01-2026'
assert change_date_format("2020-11-13") == '13-11-2020'
assert change_date_format("2021-04-26") == '26-04-2021'</s>