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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 _astype(self, dtype, **kwargs):
 """ these automatically copy, so copy=True has no effect raise on an except if raise == True """

        dtype = pandas_dtype(dtype)

        # if we are passed a datetime64[ns, tz]
        if is_datetime64tz_dtype(dtype):
            values = self.values
            if getattr(values, 'tz', None) is None:
                values = DatetimeIndex(values).tz_localize('UTC')
            values = values.tz_convert(dtype.tz)
            return self.make_block(values)

        # delegate
        return super()._astype(dtype=dtype, **kwargs)