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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_corners(self, image):
 """Find subpixel chessboard corners in image."""

        temp = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
        ret, corners = cv2.findChessboardCorners(temp,
                                                 (self.rows, self.columns))
        if not ret:
            raise ChessboardNotFoundError("No chessboard could be found.")
        cv2.cornerSubPix(temp, corners, (11, 11), (-1, -1),
                         (cv2.TERM_CRITERIA_MAX_ITER + cv2.TERM_CRITERIA_EPS,
                          30, 0.01))
        return corners