Using “is” for anything but singleton can increase costs
Count one violation each time one of the operand of is (or is not) is not None, True or False.
Why you should care
is. Most prominently it is used to check whether an variable points to
None. But the operator can examine any kind of identity. This often leads to confusion because equality of two different objects will return
forgiveness : As some exception can be tolerated, a few percentage of “is” for checking identity of two objects other than singleton should be allowed in the model.
About CAST and Highlight’s Code Insights
Over the last 25 years, CAST has leveraged unique knowledge on software quality measurement by analyzing thousands of applications and billions of lines of code. Based on this experience and community standards on programming best practices, Highlight implements hundreds of code insights across 15+ technologies to calculate health factors of a software.