Why is this an issue?

Sharing some naming conventions is a key point to make it possible for a team to efficiently collaborate. This rule allows to check that all method names match a provided regular expression.

Noncompliant code example

With default provided regular expression: ^[a-z_][a-z0-9_]*$

class MyClass:
    def MyMethod(a,b):
        ...

Compliant solution

class MyClass:
    def my_method(a,b):
        ...