To use ChromeOptions in RobotFramework you may want to do something like:
In ./project_root/my_library.py
from typing import Union
from selenium.webdriver.chrome.options import Options
def Get_Proxy_Option(url: str, port: Union[int, str]) -> Options:
options = Options()
options.add_argument(f"--proxy-server={url}:{port}")
return options
In ./project_root/my_testcase.robot
*** Settings ***
Library SeleniumLibrary
Library ./my_library.py
*** Keywords ***
Open Browser With Proxy
[Arguments] ${browser_url} ${proxy_url}=url.to.proxy ${proxy_port}=8080
${options}= Get_Proxy_Options @{ext_paths} url=${proxy_url} port=${proxy_port}
Open Browser ${url} Chrome options=${options}
ref: https://selenium-python.readthedocs.io/api.html#selenium.webdriver.chrome.options.Options.add_argument