code: def add_bases(cls, *bases):
      
      assert inspect.isclass(cls), "Expected class object"
      for mixin in bases:
          assert inspect.isclass(mixin), "Expected class object for bases"
      new_bases = (bases + cls.__bases__)
      cls.__bases__ = new_bases
docs: Add bases to class
  
      >>> class Base(object): pass
      >>> class A(Base): pass
      >>> class B(Base): pass
      >>> issubclass(A, B)
      False
      >>> add_bases(A, B)
      >>> issubclass(A, B)
      True