imports a model of name from path, returning from local model
    cache if it has been previously loaded otherwise importing

def import_model(self, name, path="floyd.db.models"):
    """imports a model of name from path, returning from local model
    cache if it has been previously loaded otherwise importing"""
    if name in self._model_cache:
      return self._model_cache[name]
  
    try:
      model = getattr(__import__(path, None, None, [name]), name)
      self._model_cache[name] = model
    except ImportError:
      return False
    return model