Forgot the Spaces
Oops, you've just written a very short paper for your science class and forgot to put spaces after the periods. Instead of retyping everything like a savage, you decided to write a program to do it for you.

The method forgotSpaces will take a single parameter str that will contain exactly 2 periods, and no period will be at the end of str, but a period could be the first character.

You may assume that no periods already have spaces after them.

forgotSpaces(".hello.there") => ". hello. there"
forgotSpaces("hi.b.ob") => "hi. b. ob"
forgotSpaces("comp.sci.rocks") => "comp. sci. rocks"
forgotSpaces(".at.the beginning") => ". at. the beginning"
forgotSpaces("..!") => ". . !"