Christmas Bird Count history report system

# - - - - -   c l a s s   C e n s u s R o w L a b e l

class CensusRowLabel(RowLabel):
    '''Row label for a row giving counts of individuals.

      Exports:
        CensusRowLabel(birdId):
          [ birdId is an abbrMod.BirdId instance ->
              return a new CensusRowLabel instance for the kind of
              bird in birdId ]
        .birdId:     [ as passed to constructor, read-only ]
    '''