Correction to exporting docs

doc/source/exporting.rst

@@ -39,13 +39,14 @@ Exporting from the API
 To export a file programatically, follow this example::
 
     import pyqtgraph as pg
+    import pyqtgraph.exporters
     
     # generate something to export
     plt = pg.plot([1,5,2,4,3])
 
     # create an exporter instance, as an argument give it
     # the item you wish to export
-    exporter = pg.exporters.ImageExporter.ImageExporter(plt.plotItem)
+    exporter = pg.exporters.ImageExporter(plt.plotItem)
 
     # set export parameters if needed
     exporter.parameters()['width'] = 100   # (note this also affects height parameter)