SVGGraph bar graph with just 1 element

Question

I'm creating the graph using a library called svggraph. Generating the graph is very simple. However I am facing an issue when my array has just 1 element. I get an error "Invalid axis: min >= max Invalid axis: min >= max"

below is my code

 $graph = new SVGGraph(800, 400);
 $datahg = array('07-2014' => 285);
 $graph->Values($datahg); 
 $graph->Render('BarGraph', true, true);

This code works when array size is more than 1. how can i draw a bar graph with just 1 item. Thanks in advance