자세한 설명은 생략한다
url = "https://5dang.ebs.co.kr/auschool/detail?courseId=BK0KAKC0000000014"
page_source = requests.get(url).text
mp3_url = re.split('wstrotu.ebs.co.kr',page_source,re.S)[1].replace(";"," ")
mp3_url2 = mp3_url.split("?")
mp3_url2[0]
url = "https://wstrotu.ebs.co.kr" + mp3_url2[0]
filename = url.split('/')[-1]
filename