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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 identify(s):
 """Identify a given string's transcription system. *s* is the string to identify. The string is checked to see if its contents are valid Pinyin, Zhuyin, or IPA. The :data:`PINYIN`, :data:`ZHUYIN`, and :data:`IPA` constants are returned to indicate the string's identity. If *s* is not a valid transcription system, then :data:`UNKNOWN` is returned. When checking for valid Pinyin or Zhuyin, testing is done on a syllable level, not a character level. For example, just because a string is composed of characters used in Pinyin, doesn't mean that it will identify as Pinyin; it must actually consist of valid Pinyin syllables. The same applies for Zhuyin. When checking for IPA, testing is only done on a character level. In other words, a string just needs to consist of Chinese IPA characters in order to identify as IPA. """

    if is_pinyin(s):
        return PINYIN
    elif is_zhuyin(s):
        return ZHUYIN
    elif is_ipa(s):
        return IPA
    else:
        return UNKNOWN