Not being able to apply "profile" option in SELENIUM_DRIVER_ARGUMENTS

[m0rtal]

I've tried -user-data-dir=r"C:\Users\user\AppData\Roaming\Mozilla\Firefox\Profiles\blah",
-profile-directory=r"C:\Users\user\AppData\Roaming\Mozilla\Firefox\Profiles\blah",
same with two dashes, changing profile path to "Local" instead of "Roaming", webdriver.FirefoxProfile(path), etc - nothing works.
What am I doing wrong?

[SurendraTamang]

Any luck?