def grep(pattern):
print("Searching for", pattern)
while True:
line = (yield)
if pattern in line:
print(line)
search = grep('coroutine')
next(search)
search.send("I love you")
search.send("Don't you love me?")
search.send("I love coroutine instead!")
search.close()
Searching for coroutine
I love coroutine instead!