text: ﻿# QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
  # Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from AlgorithmImports import *
  
  class UniverseSelectionModel:
      '''Provides a base class for universe selection models.'''
  
      def GetNextRefreshTimeUtc(self):
          '''Gets the next time the framework should invoke the `CreateUniverses` method to refresh the set of universes.'''
          return datetime.max
  
      def CreateUniverses(self, algorithm):
          '''Creates the universes for this algorithm. Called once after <see cref="IAlgorithm.Initialize"/>
          Args:
              algorithm: The algorithm instance to create universes for</param>
          Returns:
              The universes to be used by the algorithm'''
          raise NotImplementedError("Types deriving from 'UniverseSelectionModel' must implement the 'def CreateUniverses(QCAlgorithm) method.")
  