logilab-astng #69211 UnboundMethod.igetattr(self, name, context) throws TypeError: super() argument 1 must be type, not classobj [open]

I ran into a pylint problem when using it on some code that uses Mock library.
See attached files for example code that reproduces the problem, as well as the log file with results from running pylint on the code.

My astng version is 0.20.1

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