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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_control(self, char):
 """Checks whether `chars` is a control character."""

        # These are technically control characters but we count them as whitespace
        # characters.
        if char in ['\t', '\n', '\r']:
            return False
        cat = unicodedata.category(char)
        if cat.startswith('C'):
            return True
        return False