code: def getbyuuid(self, uuid):
          
          if uuid not in self._schbyuuid:
              raise KeyError('uuid {0} not registered'.format(uuid))
  
          return self._schbyuuid[uuid]
docs: Get a schema by given uuid.
  
          :param str uuid: schema uuid to retrieve.
          :rtype: Schema
          :raises: KeyError if uuid is not registered already.