Write a function multiply_values (d1, d2) that takes in two dictionaries. In both dictionaries, the keys are strings, and the values are integers. The function should return a new dictionary which contains only the keys present in both dictionaries. The value for each key should be the product of the values for that key in the two input dictionaries. This function should not alter either of the two dictionaries passed in as arguments. Examples: >>> multiply_values ({'e':5, 'h':8, 'm':3, 'o':5}, {'e':1, 'o':4, 'r':10}) {'e': 5, 'o': 20} >>> multiply_values ({'x':12, 'y':43}, {}) {} >>> multiply_values({'a':11, 'c':10, 'n':2}, {'a':1, 'c':2, 'o':3, 'n':4}) {'n': 8, 'c': 20, 'a': 11}