class Kunde:

    def __init__(self):
        self._laant = []

    def leggTilBok(self, bok):
        self._laant.append(bok)
    
    def antallBoker(self):
        return len(self._laant)

    def leverBoker(self, bibliotek):
        for bok in self._laant:
            bibliotek.leggTilBok(bok)
        self._laant = []