def _retrieveRegions(self):
    """
    Retrieve and store Python region instances for each column
    """
    self.sensors = []
    self.coarseSensors = []
    self.locationInputs = []
    self.L4Columns = []
    self.L2Columns = []
    self.L5Columns = []
    self.L6Columns = []

    for i in xrange(self.numColumns):
      self.sensors.append(
        self.network.regions["sensorInput_" + str(i)].getSelf()
      )
      self.coarseSensors.append(
        self.network.regions["coarseSensorInput_" + str(i)].getSelf()
      )
      self.locationInputs.append(
        self.network.regions["locationInput_" + str(i)].getSelf()
      )
      self.L4Columns.append(
        self.network.regions["L4Column_" + str(i)].getSelf()
      )
      self.L2Columns.append(
        self.network.regions["L2Column_" + str(i)].getSelf()
      )
      self.L5Columns.append(
        self.network.regions["L5Column_" + str(i)].getSelf()
      )
      self.L6Columns.append(
        self.network.regions["L6Column_" + str(i)].getSelf()
      )
Retrieve and store Python region instances for each column