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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 _repr_png_(self):
 """iPython display hook returns png version of image """


        data = ffi.new('l_uint8 **')
        size = ffi.new('size_t *')

        err = lept.pixWriteMemPng(data, size, self._cdata, 0)
        if err != 0:
            raise LeptonicaIOError("pixWriteMemPng")

        char_data = ffi.cast('char *', data[0])
        return ffi.buffer(char_data, size[0])[:]