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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 _get_image_numpy_dtype(self):
 """ Get the numpy dtype for the image """

        try:
            ftype = self._info['img_equiv_type']
            npy_type = _image_bitpix2npy[ftype]
        except KeyError:
            raise KeyError("unsupported fits data type: %d" % ftype)

        return npy_type