How do I check (at runtime) if one class is a subclass of another?

Let’s say that I have a class Suit and four subclasses of suit: Heart, Spade, Diamond, Club.

class Suit:
   ...
class Heart(Suit):
   ...
class Spade(Suit):
   ...
class Diamond(Suit):
   ...
class Club(Suit):
   ...

I have a method which receives a suit as a parameter, which is a class object, not an instance. More precisely, it may receive only one of the four values: Heart, Spade, Diamond, Club. How can I make an assertion which ensures such a thing? Something like:

def my_method(suit):
   assert(suit subclass of Suit)
   ...

I’m using Python 3.