Why is this an issue?
When a function is designed to return an invariant value, it may be poor design, but it shouldn’t adversely affect the outcome of your program.
However, when it happens on all paths through the logic, it is surely a bug.
This rule raises an issue when a function contains several return statements that all return the same value.
Noncompliant code example
def foo(a): # NonCompliant
b = 12
if a == 1: