[오류 메세지] ValueError: time data "13-04-2018" doesn't match format "%m-%d-%Y", at position 8. You might want to try: - passing `format` if your strings have a consistent format; - passing `format='ISO8601'` if your strings are all ISO8601 but not necessarily in exactly the same format; - passing `format='mixed'`, and the format will be inferred for each element individually. You might want to use ..
