python 使用三引号时容易犯的小错误

# -*- coding:utf-8 -*-
from tkinter import *
from tkinter import ttk
from PIL import ImageTk
import qrcode
class QRcodeImage(object):
  '''生成二维码图片类'''

  def __init__(self, content, fcolor=None, bcolor=None, size=None):
    '''
    参数说明：
    content：二维码图片的文本内容
    fcolor：二维码图片的前景色
    bcolor：二维码图片的背景色
    size:二维码大小
    '''
    qr = qrcode.QRCode(version=2,
              error_correction=qrcode.constants.ERROR_CORRECT_L, #容错率
              box_size=8,
              border=2) # 实例化QRCode类，得到qr对象
    qr.add_data(content) # 二维码内容添加到图片中
    qr.make(fit=True) # 图片中的二维码大小自适应，以保证二维码内容能完整绘制
    if fcolor == None: fcolor = 'black' #默认前景色为黑色
    if bcolor == None:bcolor = 'white' #默认背景色为白色
    img = qr.make_image(fill_color=fcolor,
              back_color=bcolor) #生成彩色二维码图片
    img = img.convert(mode="RGBA") # 将图片的模式转换为彩色透明模式
    if size == None: size = 150 #默认图片大小
    self.img = img.resize((size, size))

  def getPhotoImage(self):
    '''转换为PhotoImage'''
    tkimg = ImageTk.PhotoImage(self.img)
    return tkimg
def cvfill():
  cv.create_window(200, 50, window=lbimg1, width=155, height=155,
           anchor=NW,
           )
  cv.create_window(50, 50, window=lbimg2, width=155, height=155,
         anchor=NW,
         )
  global img1
  img1 = QRcodeImage(content).getPhotoImage()
  lbimg1.config(image=img1)
  content1='''BEGIN:VCARD
  FN:steven
  TITLE:Drector
  TEL;TYPE=CELL:15201011234
  NOTE:
  END:VCARD '''
  global img2
  img2=QRcodeImage(content1).getPhotoImage()
  lbimg2.config(image=img2)
root = Tk()


cv = Canvas(root, width='94m', height='54m', bg='#F0F8FF',
    highlightbackground='gold',
    highlightthickness=2,
    )
cv.pack(pady=10)

lbimg1 = Label()
lbimg2 = Label()
content='''BEGIN:VCARD
FN:steven
TITLE:Drector
TEL;TYPE=CELL:15201011234
NOTE:
END:VCARD '''
cvfill()
mainloop()

content = BEGIN:VCARD\nFN:steven\nTITLE:Drector\nTEL;TYPE=CELL:15201011234\nNOTE:\nEND:VCARD

content1 = BEGIN:VCARD\n  FN:steven\n  TITLE:Drector\n  TEL;TYPE=CELL:15201011234\n  NOTE:\n  END:VCARD