code: def _ctx_get_or_create(self, key, creation_function, context, **kw):
          
  
          if not self.template.cache_enabled:
              return creation_function()
  
          return self.impl.get_or_create(
              key,
              creation_function,
              **self._get_cache_kw(kw, context))
docs: Retrieve a value from the cache, using the given creation function
          to generate a new value.