Python The function f2 gets a string s and 2 characters : cl , c2. It returns as a result a new string that includes all characters from s as appear in s, but adds cl before every appearance of c2. If c2 does not appear, then result is as S. examples : I f2 ('abaca','d', 'a') ==' dabdacda' f2 ('ebece', 'd', 'a') =='ebece' I Complete the missing code of f2, as follows : def f2 (s, c1, c2): return Requirements : The code to be completed MUST be written ONLY in the signed place, after the word return. The function must NOT be recursive