old_contents: def get_full_name_or_username(user):
      result = []
      if user.first_name or user.last_name:
          if user.first_name:
              result.append(user.first_name)
          if user.last_name:
              result.append(user.last_name)
      else:
          result.append(user.username)
  
      return " ".join(result)
new_contents: def get_full_name_or_username(user):
      result = []
      if user.first_name or user.last_name:
          if user.last_name:
              result.append(user.last_name)
          if user.first_name:
              result.append(user.first_name)
      else:
          result.append(user.username)
  
      return " ".join(result)
subject: fix name