How to run this command on windows system ENV=development python app.py

[basavarajb]

I' unable to execute the ENV=development python app.py on windows 10 .
I tried executing the following command

set ENV=development & python app.py

Output:
DEFAULT 1
{'b1': [1, 2, 3], 'b2': ['foo', 'bar'], 'b3': {'c1': 1, 'c2': 'DEFAULT 2'}}
DEFAULT 2
config.some_key_only_for_dev 'some_key_only_for_dev'
config.some_key_only_for_foo 'some_key_only_for_foo'
config.some_key_only_for_foo 'some_key_only_for_prod'
$$$
Excepted result
DEFAULT 1
{'b1': [1, 2, 3], 'b2': ['DEV 1'], 'b3': {'c1': 1, 'c2': 'DEV 2'}}
DEV 2
config.some_key_only_for_dev True
config.some_key_only_for_foo 'some_key_only_for_foo'
config.some_key_only_for_foo 'some_key_only_for_prod'

[eric-nextsense]

$env:ENV="development"; python app.py

This should work in powershell