code: def rfunc(a, rfunc=None, rep=0.75, **kwargs):
      
      if float(ma.count(a)) / ma.size(a) < rep:
          return ma.masked
      else:
          if rfunc is None:
              return a
          return rfunc(a, **kwargs)
docs: Applies func on a if a comes with a representativity coefficient rep,
      i.e. ma.count(a)/ma.size(a)>=rep. If not, returns a masked array