human
Complete this python program:
def _merge_and_sort_errors(errors):
assistant
#Here is the Python code you requested.

    """Merge errors from one or more lists of errors and then return
    them, sorted by recency.
    We allow None in place of an error list.
    """
    key_to_error = {}
    for error in errors:
        key = _time_sort_key(error)
        key_to_error.setdefault(key, {})
        key_to_error[key].update(error)
    def sort_key(key_and_error):
        (key, error) = key_and_error
        return (key[0], bool(error.get('task_error')), key[1:])
    return [error for (key, error) in sorted(key_to_error.items(), key=sort_key, reverse=True)]