Unused parameters are misleading. Whatever the value passed to such parameters is, the behavior will be the same.

Noncompliant Code Example

def do_something(a, b): # "b" is unused
  return compute(a)

Compliant Solution

def do_something(a):
  return compute(a)

Exceptions

Overriding methods are ignored.

class C(B):
  def do_something(self, a, b): # no issue reported on b
    return self.compute(a)
}

Throwaway variables _.

def do_something(a, _): # no issue reported on _
  return compute(a)