code: def apply_extra_context(extra_context, context):
      
      for key, value in six.iteritems(extra_context):
          if callable(value):
              context[key] = value()
          else:
              context[key] = value
docs: Adds items from extra_context dict to context.  If a value in extra_context
      is callable, then it is called and the result is added to context.