[Python] I can't figure out why `isinstance()` returns `True` for these subclasses

I'm using the Python package ariadne, v0.23.0.

I wrote a utility to scan my code for instances of ariadne.types.SchemaBindable, but it's also unintentionally picking up the SchemaBindable subclasses that I've imported:

ariadne.input.InputType( SchemaBindable )
ariadne.objects.ObjectType( SchemaBindable )
ariadne.scalars.ScalarType( SchemaBindable )
ariadne.unions.UnionType( SchemaBindable )


I ran a test in a Python shell, and sure enough, isinstance() is returning True when comparing those classes to SchemaBindable:

isinstance( ObjectType, SchemaBindable ) -> True
...etc...


SchemaBindable even appears to be an instance of itself:

isinstance( SchemaBindable, SchemaBindable ) -> True


Meanwhile, issubclass() continues to also return True:

issubclass( ObjectType, SchemaBindable ) -> True


Make it make sense.

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