def getEntity(self, name, request):
        """Retrieve an entity from me.

        I will first attempt to retrieve an entity statically; static entities
        will obscure dynamic ones.  If that fails, I will retrieve the entity
        dynamically.

        If I cannot retrieve an entity, I will return 'None'.
        """
        ent = self.getStaticEntity(name)
        if ent is not None:
            return ent
        ent = self.getDynamicEntity(name, request)
        if ent is not None:
            return ent
        return None
Retrieve an entity from me.

        I will first attempt to retrieve an entity statically; static entities
        will obscure dynamic ones.  If that fails, I will retrieve the entity
        dynamically.

        If I cannot retrieve an entity, I will return 'None'.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/roots.py