How to use the pottery.epottery function in pottery

def requestAvatarId(self, credentials):
        u, p = credentials.username, credentials.password
        u = u.lower()
        try:
            if self.players[u][0] == p:
                return u
            raise epottery.BadPassword()
        except KeyError:
            raise epottery.NoSuchUser()

def requestAvatarId(self, credentials):
        u, p = credentials.username, credentials.password
        u = u.lower()
        try:
            if self.players[u][0] == p:
                return u
            raise epottery.BadPassword()
        except KeyError:
            raise epottery.NoSuchUser()

def ebAmbiguity(err):
        err.trap(epottery.AmbiguousArgument)
        exc = err.value
        if len(exc.objects) == 0:
            transport.write(getattr(err.value.action, err.value.part + "NotAvailable", "Who's that?") + "\r\n")
        else:
            transport.write("Could you be more specific?\r\n")

def ebParse(err):
        err.trap(epottery.NoSuchCommand)
        # transport.write('Bad command or filename\r\n> ')
        transport.write('Bad command or filename\r\n')