AttributeError: ‘Polygon‘ object has no property ‘normed‘ [How to Solve]

1. Problem description

An error occurs when drawing the histogram

2. Solution

Wrong pyplot.hist(heights, 20, normed=True, histtype='step', cumulative=True)
Right pyplot.hist(heights, 20, density=True, histtype='step', cumulative=True)
The #normed parameter is replaced by density, which may be a version problem.