[Tutor] Learning class code and function

[jarod_v6 at libero.it]

Dear all, I continue to try to understand some code:
class Tutto():

    def __init__(self):
        print "Ok"
   #@property
    def readsets(self,nome):
        self.nome = nome
        self._readsets = parse_tutto_readset_file(self.nome)
        return self._readsets

Why If uncomment the decorator the code not work:

p = Tutto()

p.readsets("/home/mauro/Desktop/readset.csv")

TypeError: readsets() takes exactly 2 arguments (1 given)

thanks so muc? Could you suggest me some readings for better understand class structure?