pyperclip.copy()出问题

Question

import pyperclip
text=pyperclip.paste()

print(text)

TODO: Separate lines and add stars.

lines=text.split('\n')

print(lines)

for i in range(len(lines)): #loop through all indexes in the 'lines' list
lines[i]='* '+lines[i] #add star to each string in 'lines' list
text='\n'.join(lines)

print(text)

print(pyperclip.copy(text)) #>>>这个位置打印结果为None
不清楚哪里有问题