How to make this dictionary-generating code more efficient?

[Mark17]

My code below works. I used a second variable (count) to generate the dictionary. How could I have done this more efficiently?

import random
str = "abcdefg"
print()
print(' This program randomly generates a cipher dictionary from the string',str,end="")
print('.')
print(' Cipher dictionary is:')

def make_cipher_dict(str):
    CIPHER_DICT = {}
    lst = list(str)
    sndlst = list(str)
    random.shuffle(sndlst) #random method changes specified list rather than creating new list
#    print(lst)  DEBUG
#    print(sndlst)  DEBUG
#    quit()  DEBUG
    count = 0
    for a in lst:
        CIPHER_DICT[a] = sndlst[count]
        count = count + 1
    print("",CIPHER_DICT)
    return;

make_cipher_dict(str)