import random
import itertools


def random_tuple_list(lst1, lst2, lb=1):
    """
    Generate a random list of tuples (x,y) where x is in lst1 and y is in lst2  
    """
    len_lst1 = len(lst1) 
    len_lst2 = len(lst2) 
    k = random.randint(lb,max(len_lst1,len_lst2))
    return random.sample(list(itertools.product(lst1,lst2)),k)