python как с помощью selenium использовать прокси

from selenium import webdriver

PROXY = "<HOST:PORT>"
webdriver.DesiredCapabilities.FIREFOX['proxy'] = {
    "httpProxy": PROXY,
    "ftpProxy": PROXY,
    "sslProxy": PROXY,
    "proxyType": "MANUAL",

}

with webdriver.Firefox() as driver:
    # Open URL
    driver.get("https://selenium.dev")

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