docs: def filterByFilter(self, filterName):
          """
          Swap L{baseConstraint} with the result of calling
          L{IPeopleFilter.getPeopleQueryComparison} on the named filter.
  
          @type filterName: C{unicode}
          """
          filter = self.filters[filterName]
          self.baseConstraint = filter.getPeopleQueryComparison(self.store)