$chart->set_title('PIE CHART');
$chart->add_series($sales);
$chart->set_labels($labels);
$chart2 = new \core\chart_pie();
$chart2->set_title('DOUGHNUT CHART');
$chart2->set_doughnut(true);
$chart2->add_series($sales);
$chart2->set_labels($labels);
$chart3 = new \core\chart_line();
$chart3->set_title('TENSIONED LINES CHART');
$chart3->add_series($sales);
$chart3->add_series($expenses);
$chart3->set_labels($labels);
$chart4 = new \core\chart_line();
$chart4->set_smooth(true);
$chart4->set_title('SMOOTH LINES CHART');
$chart4->add_series($sales);
$chart4->add_series($expenses);
$chart4->set_labels($labels);
$chart5 = new \core\chart_bar();
$chart5->set_title('BAR CHART');
$chart5->add_series($sales);
$chart5->add_series($expenses);
$chart5->set_labels($labels);
$chart6 = new \core\chart_bar();
$chart6->set_title('HORIZONTAL BAR CHART');
$chart6->set_horizontal(true);
$chart6->add_series($sales);
$chart6->add_series($expenses);
$chart6->set_labels($labels);
$chart7 = new \core\chart_bar();
