# return the last value of a (pointer-based) linked list in Python, with error

class cons:
    def __init__(self,a,b):
        self.car = a
        self.cdr = b
# cons class

M = cons(2,cons(3,cons(5,cons(7,None))))

def foreach(m,action):
    while m!=None:
        action(m.car)
        m = m.cdr
#foreach

foreach(M, lambda x: print(x,end=" "))  # prints list
    

def last(m):  # return last interger in a list
    while m.cdr!=None:
        m = m.cdr
    return m
#last

print()
print( last(M) )  # no erorr, of course not
print( last(M) + 1 )