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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 is_unicode_string(string):
 """Validates that we are some kinda unicode string"""

    try:
        if sys.version_info >= (3, 0):
            # isn't a python 3 str actually unicode
            if not isinstance(string, str):
                string.decode('utf-8')

        else:
            string.decode('utf-8')
    except UnicodeError:
        raise aomi.exceptions.Validation('Not a unicode string')