In some cases a comparison with operators ==, or != will always return True or always return False. When this happens, the comparison and all its dependent code can simply be removed. This includes:

• comparing None with a value which will always be None.
• comparing unrelated builtin types such as string and integer.
• comparing class instances which do not implement __eq__, or __ne__ if != is used, to an object of a different type (builtin or from an unrelated class which also doesn't implement __eq__ or __ne__).

Noncompliant Code Example

mynone = None

foo = mynone == None  # Noncompliant. Always True.

foo = 1 == "1"  # Noncompliant. Always False.

foo = 1 != "1"  # Noncompliant. Always True.

class A:
    pass

myvar = A() == 1  # Noncompliant. Always False.
myvar = A() != 1  # Noncompliant. Always True.

class Ne:
    def __ne__(self, other):
        return True

myvar = Ne() == 1  # Noncompliant. Always False. "__eq__" does not call "__ne__" by default
myvar = 1 == Ne()  # Noncompliant. Always False.
myvar = Ne() != 1  # Ok
myvar = 1 != Ne()  # Ok

Compliant Solution

foo = 1 == int("1")

foo = str(1) != "1"

class Eq:
    def __eq__(self, other):
        return True

myvar = Eq() == 1
myvar = 1 == Eq()
myvar = Eq() != 1  # Ok. "__ne__" calls "__eq__" by default
myvar = 1 != Eq()