Unable to find a matching set of capabilities with selenium 3.4.3, firefox 54.0 and gecko driver 0.17

I don’t see any significant error in your code as such.

It is to be noted that the current Selenium-Python binding is unstable with geckodriver and looks to be Architecture specific. You can find the github discussion and merge here. So you may additionally need to pass the absolute path of the firefox binary as firefox_binary argument while initializing the webdriver

Here is your own code with a simple tweak which opens the Mozilla Firefox browser:

from selenium import webdriver
from selenium.webdriver.firefox.firefox_binary import FirefoxBinary

if __name__ == '__main__':

    binary = FirefoxBinary('C:\\Program Files\\Mozilla Firefox\\firefox.exe')
    driver = webdriver.Firefox(firefox_binary=binary, executable_path="C:\\path\\to\\geckodriver.exe")