message: Add better error handling in getLeaderGroupTitle
diff: @@ -52,5 +52,5 @@ function getLeaderGroupTitle (groupSize: number): string {
  if (groupSize > 8) return 'board'
  if (groupSize > 3) return 'committee'
  if (groupSize > 2) return 'triumvirate'
  - return ''
  + throw new Error('Invalid group size.')
  }
  