code: def setLocalAreaDensity(self, localAreaDensity):
      
      assert(localAreaDensity > 0 and localAreaDensity <= 1)
      self._localAreaDensity = localAreaDensity
      self._numActiveColumnsPerInhArea = 0
docs: Sets the local area density. Invalidates the 'numActiveColumnsPerInhArea'
      parameter
      
      :param localAreaDensity: (float) value to set