code: def _bumpUpWeakColumns(self):
      
      weakColumns = numpy.where(self._overlapDutyCycles
                                  < self._minOverlapDutyCycles)[0]
      for columnIndex in weakColumns:
        perm = self._permanences[columnIndex].astype(realDType)
        maskPotential = numpy.where(self._potentialPools[columnIndex] > 0)[0]
        perm[maskPotential] += self._synPermBelowStimulusInc
        self._updatePermanencesForColumn(perm, columnIndex, raisePerm=False)
docs: This method increases the permanence values of synapses of columns whose
      activity level has been too low. Such columns are identified by having an
      overlap duty cycle that drops too much below those of their peers. The
      permanence values for such columns are increased.