code: def dashes(phone):
      
      if isinstance(phone, str):
          if phone.startswith("+1"):
              return "1-" + "-".join((phone[2:5], phone[5:8], phone[8:]))
          elif len(phone) == 10:
              return "-".join((phone[:3], phone[3:6], phone[6:]))
          else:
              return phone
      else:
          return phone
docs: Returns the phone number formatted with dashes.