import random

def count( n ):
    """
    purpose: simulate n rolls of two dice. each time get their total
    """
    result = 0
    for i in range( 0, n ): # this loops through the values from 0 to n-1 (up to and not including n)
        dice1 = random.randrange(1, 7)
        dice2 = random.randrange(1, 7)
        roll = dice1 + dice2
        if ( roll == 12 ):
            result = result + 1
    return result
# print(count(36))
# print(count(3600))

x = [3, 1, 4, 5]
print("x=", x)

x.append( 7 ) # append function returns None. Its purpose is to change the list itself
print("x=", x)

def g( items, n ): # contents of the list will be changed, so we return None. We return a list if we're creating a copy
    items.append( n )
    return None

g(x, 12)
print("x=", x)


def metric( d ):
    list1 = d.keys()
    list2 = d.values()

    result = True 
    for k in list1:
        v1 = d.get( k ) # get the value v1 for key k.       k : v1
        v2 = d.get( v1 ) # get the value v2 for key v1     v1 : v2
        if ( v2 != k ): # we want k : v1, and v1 : k. If this isn't true, then it's not symmetric
            result = False
    return result