import os
print(os.getenv('ASDF'))
os.putenv('ASDF', 'FOO')
print(os.getenv('ASDF'))
print()
print(os.getenv('TMPDIR'))
os.unsetenv('TMPDIR')
print(os.getenv('TMPDIR'))
aW1wb3J0IG9zCgpwcmludChvcy5nZXRlbnYoJ0FTREYnKSkKb3MucHV0ZW52KCdBU0RGJywgJ0ZPTycpCnByaW50KG9zLmdldGVudignQVNERicpKQoKcHJpbnQoKQoKcHJpbnQob3MuZ2V0ZW52KCdUTVBESVInKSkKb3MudW5zZXRlbnYoJ1RNUERJUicpCnByaW50KG9zLmdldGVudignVE1QRElSJykp