Sign-Up Desk

A club checks every new username before it's saved.

Write two functions:

1. clean_username(name) removes spaces from both ends and makes the name lowercase. Then:
   • if the cleaned name is empty, raise ValueError("username is empty")
   • if it has more than 10 characters, raise ValueError("username is too long")
   • otherwise return the cleaned name
2. sign_up(names) runs clean_username on every name in order. It returns a dictionary:
   • "accepted": the list of cleaned names that worked
   • "refused": the list of error messages, as text, for the ones that didn't