gistfile1.py

class ExtraValueMixin(object):
  value = 1
  def get_value(self):
    return self.value
    
  def get_context_data(self, *args, **kwargs):
    context = .... super ... get_context_data
    context['extra_value'] = self.get_value()
    return context
    
class MyCusotmView(ExtraValueMixin, DetailView):
  model = MyModel
  

class MyOtherView(ExtraValueMixin, TemplateView):
  template_name = "template.html"
  
  

class A(object):
def f(self):
print "A"

class B(object):
def f(self):
print "B"

class AB(A,B):
pass

class BA(B,A):
pass

BA().f()
AB().f()