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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_utf8(obj):
 """Walks a simple data structure, converting unicode to byte string. Supports lists, tuples, and dictionaries. """

    if isinstance(obj, unicode_type):
        return _utf8(obj)
    elif isinstance(obj, dict):
        return dict((to_utf8(k), to_utf8(v)) for (k, v) in obj.items())
    elif isinstance(obj, list):
        return list(to_utf8(i) for i in obj)
    elif isinstance(obj, tuple):
        return tuple(to_utf8(i) for i in obj)

    return obj