def combinations_list(list1):
    
    if len(list1) == 0:
        return [[]]
    result = []
    for el in combinations_list(list1[1:]):
        result += [el, el+[list1[0]]]
    return result
def is_not_prime(n):
    import math
    
    result = False
    for i in range(2,int(math.sqrt(n)) + 1):
        if n % i == 0:
            result = True
    return result