2-fer is short for "two for one": One for you and one for me.
Given a name, return a string with the message:
One for name, one for me.
Where "name" is the given name.
However, if the name is missing, return the string:
One for you, one for me.
Here are some examples:
|Name||String to return|
|Alice||One for Alice, one for me.|
|Bob||One for Bob, one for me.|
|One for you, one for me.|
|Zaphod||One for Zaphod, one for me.|