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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 seek(self, idx):
 """Sets the current read pointer position. This function is internally called by `read_idx(idx)` to find the current reader pointer position. It doesn't return anything."""

        assert not self.writable
        self._check_pid(allow_reset=True)
        pos = ctypes.c_size_t(self.idx[idx])
        check_call(_LIB.MXRecordIOReaderSeek(self.handle, pos))