Multiple inheritance, super() and changing signature

Ben Finney ben+python at
Fri Jun 3 16:19:15 EDT 2016

Nagy László Zsolt <gandalf at> writes:

> Fortunately, I can change all of the classes, and extracting the
> common parameter into a common base class worked.

This is why Liskov's Substitution Principle is good: Thinking of it as a
law helps lead to better design.

In this case, the same parameter doing different things in different
sub-classes meant that instances of those sub-classes had difficulty
substituting for the superclass. Interrogating the design against the
LSP reveals that.

> Problem solved. Thank you for all your help!
> Cooperative classes are fantastic! :-)

I'm glad you discovered them :-)

 \       “Truth is stranger than fiction, but it is because fiction is |
  `\     obliged to stick to possibilities, truth isn't.” —Mark Twain, |
_o__)                                          _Following the Equator_ |
Ben Finney

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