Add a line after a specific line

[morgandebray]

Hi, I'm trying to add new line after a particular line.

for line in file :
   if line.startswith('/22/'):
            #ADD LINE AFTER THIS line
            #WITH "TEST" AS CONTENT

but file.write("TEST") add a line at the end of the file
I want the "TEST" line to be added after the "/22/" line