6.) friends = ('sam', 'andy', 'mary', 'andy', 'john', 'andy', 'mary')

Write a python program which does the following:

a.) for the above string, calculate the number of times "andy" appears in the tuple.

b.) change sam with smith

c.) print index of john

7.) dict = {'data1': 100, 'data2': 54, 'data3': 247, 'data4': 100, 'data5': 54, 'data6': 247}

for the given dictionary, write a program that does the following:

a.) print all keys

b.) print all values

c.) calculate length