error in making barchart using reportlab auto tool

I am getting the following error when trying to create a bar chart using the reportlab tool for chart creation. I am making a DataAwareDrawing chart. Please let me know what can I do.

Traceback (most recent call last):
File "C:\Python26\Lib\site-packages\rlextra\graphics\guiedit\guiedit.py", line 1582, in attrChange

self.redraw()

File "C:\Python26\Lib\site-packages\rlextra\graphics\guiedit\guiedit.py", line 1234, in redraw

self.newDrawing()

File "C:\Python26\Lib\site-packages\rlextra\graphics\guiedit\guiedit.py", line 1465, in newDrawing

self.project.getSample()

File "C:\Python26\Lib\site-packages\rlextra\graphics\guiedit\guiedit.py", line 736, in getSample

exec "%s\n_x=%s()\n" % (txt,self.className) in locals(开发者_如何学运维)

File "<string>", line 13, in <module>

File "<string>", line 9, in __init__

File "C:\Python26\lib\site-packages\reportlab\graphics\charts\barcharts.py", line 91, in __init__

assert self.__class__.__name__ not in ('BarChart','BarChart3D'), 'Abstract Class %s 

Instantiated' % self.__class__.__name__

AssertionError: Abstract Class BarChart Instantiated

Couldn't set self._add(self,BarChart(),name='bar',validate=None,desc=None)

You attempt to create a BarChart object. Use VerticalBarChart instead.