Write a function called reformatName. It should take a single String argument containing a name formatted like:

• "Challen,Chuchu"
• or, "Challen, Chuchu "
• or, " Challen , Chuchu"

That is, the last name first, followed by a comma, and then the first name, but each possibly surrounding by whitespace. In all cases above you should return "Chuchu Challen". If the passed String is null, you should return null. You may find the String methods split and trim useful.