code: def _sanitize_acronyms(unsafe_acronyms):
      
      valid_acronym = regex.compile(u'^[\p{Ll}\p{Lu}\p{Nd}]+$')
      acronyms = []
      for a in unsafe_acronyms:
          if valid_acronym.match(a):
              acronyms.append(a.upper())
          else:
              raise InvalidAcronymError(a)
      return acronyms
docs: Check acronyms against regex.
  
      Normalize valid acronyms to upper-case.
      If an invalid acronym is encountered raise InvalidAcronymError.