
    Create a function that converts student assessment dates from the school database format (yyyy-mm-dd) to the assignment difficulty tracking system's required format (dd-mm-yyyy) to ensure proper performance trend analysis. The function should handle any valid academic year date and maintain chronological accuracy for historical performance data tracking.
    

    
import re

def change_date_format(dt):
    """
    Create a function that converts student assessment dates from the school database format (yyyy-mm-dd) to the assignment difficulty tracking system's required format (dd-mm-yyyy) to ensure proper performance trend analysis. The function should handle any valid academic year date and maintain chronological accuracy for historical performance data tracking.
    

    """
import re

def change_date_format(dt):
    """
    Create a function that converts student assessment dates from the school database format (yyyy-mm-dd) to the assignment difficulty tracking system's required format (dd-mm-yyyy) to ensure proper performance trend analysis. The function should handle any valid academic year date and maintain chronological accuracy for historical performance data tracking.
    

    """
    return re.sub('(\\d{4})-(\\d{1,2})-(\\d{1,2})', '\\3-\\2-\\1', dt)