Fatal error: Uncaught Error: Class 'Plot' not found in /opt/lampp/htdocs/portal/jpgraph-1.27.1/jpgraph/src/New folder/jpgraph_contour.php:388 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/portal/jpgraph-1.27.1/jpgraph/src/New folder/jpgraph_contour.php on line 388