file handling

[sivareddy]

import os, sys
from subprocess import Popen,PIPE
myfs=input("myfs=")
try:
#grep myfs /etc/fstab
  p1 = Popen(['grep',myfs,'/etc/fstab'], stdout=PIPE)
  p1.communicate()[0].decode('utf-8').split()[1]
  p1.stdout.close()
except IndexError:
  with open("/etc/fstab", "a+") as f:
      f.write(`df -h|grep myfs|awk '{print $1,$6}'` + ext4 + defaults + 1 + 2)
      f.close()

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i am getting an error like this

Error:
[root@localhost mylvm]# python test9.py
  File "test9.py", line 11
    f.write(`df -h|grep myfs|awk '{print $1,$6}'` + ext4 + defaults + 1 + 2)
            ^
SyntaxError: invalid syntax

i need to update like this in /etc/fstab

/dev/mapper/vgdata-lvmyfssiva /myfs/siva ext4 defaults 1 2