OS command via python subprocess module

[alinaveed786]

Not working either with os.chdir.

#!/usr/bin/python
import os
import subprocess


subprocess.run('echo $ORACLE_HOME', shell=True)

os.chdir("'$ORACLE_HOME'")

subprocess.run('pwd', shell=True)

Error

/u01/app/oracle/product/12.1.0.2/db_1
Traceback (most recent call last):
  File "/u02/scripts/Patching/Ping.py", line 9, in <module>
    os.chdir("'$ORACLE_HOME'")
FileNotFoundError: [Errno 2] No such file or directory: "'$ORACLE_HOME'"