[SOLVED]passing a lot of information to subprocess.call()

[Barrowman]

This is all running under python 3.5.2
Well after a lot more googling I have found a different approach instead of subprocess.call

cat = subprocess.Popen(['cat', '/home/norman/khconf/second.txt'], 
                        stdout=subprocess.PIPE,
                        )

sort = subprocess.Popen(['sort'],
                        stdin=cat.stdout,
                        stdout=subprocess.PIPE,
                        )

uniq = subprocess.Popen(['uniq'],
                        stdin=sort.stdout,
                        stdout=subprocess.PIPE,
                        )


end_of_pipe = uniq.stdout
lastfile = docs + "/third.txt"

lastone = open(lastfile, 'w')
lastone.write("Hello World")
for line in end_of_pipe:
    lastone.write(line)

I get no errors but third.txt only contains the "Hello World"
I modified the code from https://pymotw.com/2/subprocess/
Can anyone suggest how I can fix this please?