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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _untag_sentence(tagged_sentence):
 """Removes all tags in the sentence, returning the original sentence without Medscan annotations. Parameters tagged_sentence : str The tagged sentence Returns ------- untagged_sentence : str Sentence with tags and annotations stripped out """

    untagged_sentence = TAG_PATT.sub('\\2', tagged_sentence)
    clean_sentence = JUNK_PATT.sub('', untagged_sentence)
    return clean_sentence.strip()