Cheat-> Python - 3

lst = [1,2,3]
lst.append(4)
lst
# [1,2,3,4]
lst.count(2)
# 1

def is_prime(num):
    '''
    Naive method of checking for primes.
    '''
    for n in range(2,num):
        if num % n == 0:
            print(num,'is not prime')
            break
    else: # If never mod zero, then prime
        print(num,'is prime!')

#MAP
my_nums = [1,2,3,4]

list(map(lambda num: num ** 2, my_nums))

def square(x):
    return x**2
list(map(square, mylist))
# [1,4,9,16]

list(filter(lambda n: n % 2 == 0,my_nums))

def check_even(x):
    return x%2==0
list(filter(check_even, mylist))
# [2,4]

def myfunc(*args):
    return sum(args)*.05

myfunc(40,60,20)
# 6.0

def myfunc(**kwargs):
    if 'juice' in kwargs:
        print(f"May I have some {kwargs['juice']} juice?")
    else:
        pass

myfunc(juice='orange')
# May I have some orange juice?