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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 to_ipa(s, delimiter=' ', all_readings=False, container='[]'):
 """Convert a string's Chinese characters to IPA. *s* is a string containing Chinese characters. *delimiter* is the character used to indicate word boundaries in *s*. This is used to differentiate between words and characters so that a more accurate reading can be returned. *all_readings* is a boolean value indicating whether or not to return all possible readings in the case of words/characters that have multiple readings. *container* is a two character string that is used to enclose words/characters if *all_readings* is ``True``. The default ``'[]'`` is used like this: ``'[READING1/READING2]'``. Characters not recognized as Chinese are left untouched. """

    numbered_pinyin = to_pinyin(s, delimiter, all_readings, container, False)
    ipa = pinyin_to_ipa(numbered_pinyin)
    return ipa