Testing Bootstrap select dropdown field with Selenium (Python)

I am building a Flask app that uses the Bootstrap CSS framework. Forms fields are generated with WTForms via the Flask-WTF extension.

One of my forms includes a select field:

<div class="form-group ">
    <label class="control-label" for="surface">Surface</label>

    <select class="form-control" id="surface" name="surface">
        <option value="clay">Clay</option>
        <option value="hard">Hard</option>
        <option value="grass">Grass</option>

My functional tests with Selenium went fine until I changed the desired test value from the default ("Clay") to a different option ("Hard"). (duh!!) So I knew I did something wrong and looked for the correct way to choose an option from a select field.

All the tests use the Selenium WebDriver.

from selenium import webdriver

browser = webdriver.Firefox()

How it doesn't work

Via Google and Stackoverflow I found several possible solutions, none of which worked for me.
 My favorite one uses the Selenium Webdriver Select class:

from selenium.webdriver.support.ui import Select

select = Select(browser.find_element_by_id('surface'))

Then there are solutions using the find_element_by_xpath method:

option = browser.find_element_by_xpath("//select[@id='surface']/option[@value='hard']")

or find_element_by_css_selector:

option = browser.find_element_by_css_selector("select#surface > option[value='hard']")

and one other looking for the option fields:

dropdown = browser.find_element_by_id('surface')
for option in dropdown.find_elements_by_tag_name('option'):
    if option.text == 'Hard':

Apparently, Bootstrap does not play with Selenium. Or whatever.

How it does works

I don't remember where I got the idea to my solution, but it's simple and obvious. It selects the dropdown menu, and then types in the text that I want to click. Then hits enter and voilá, the desired option is selected.

from selenium.webdriver.common.keys import Keys

dropdown = browser.find_element_by_id('surface')

If you have a better way to select an option in a Bootstrap select field with the Selenium WebDriver, then please tell me!