[Add] 유튜브 자막을 xml으로 추출(PyTube 사용)

+from pytube import YouTube
+
+video_url = 'https://www.youtube.com/watch?v=Zg3j6anDU6U'
+yt = YouTube(video_url)
+caption = yt.captions.get_by_language_code('ko')
+if(caption == None):
+    caption = yt.captions.all()[0]
+caption.xml_captions()
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