使用发送方法时，为什么产量会跳过

Question

guests = ["Tim,22",
"Tonya,45",
"Mary,12",
"Ann,32",
"Beth,20",
"Sam,5",
"Manny,76",
"Kenton,15",
"Kenny,27",
"Dixie,46",
"Mallory,32",
"Julian,4",
"Edward,71",
"Rose,65"]

def read_guestlist(file_name):
  while True:
    for person in guests:
      name, age = person.split(",")

      new_guest = yield name
      if new_guest != None: 
        new_name, new_age = new_guest.split(",")
        name = new_name
        yield "This never gets printed"
        yield new_name

guestlist = read_guestlist(guests)

counter = 0
for name in guestlist:
  if counter == 5:
    guestlist.send("Jane,35") 
    counter += 1 
  elif counter == 10:
    guestlist.send("Pontus,35")
    counter += 1
  print(name)
  counter += 1
  if counter > 17:
    break

我已经玩过此代码了一段时间，每次我都使用发送一个收益> yart被跳过。在这种情况下，这是yart：屈服“这永远不会打印”。我的问题是：为什么每次我使用发送方法时，为什么特定的收益都会跳过？