Looking for an example of how to use `element_selection_state_to_be()` in Selenium

Wanting to use Expected Conditions in Selenium to wait for an option in a dropdown to be selected.

One of the methods that can be used is element_located_selection_state_to_be(locator, isSelected)

However, I haven't been able to find an example of a locator for the option that should be selected.

HTML:

<select id=mylist>
  <option value="item1">First Item</option>
  <option value="item2">Second Item</option>
  <option value="item3">Third Item</option>
</select>

Python:

from selenium.webdriver.support import expected_conditions as ec
from selenium.webdriver.support.ui import Select
from selenium.webdriver.support.ui import WebDriverWait
...

# 'browser' is the WebDriver
# find the dropdown box
dropdown = (
    browser.find_element(
        by=By.ID,
        value='mylist'
    )
)

# select the desired option
dropdown_select = Select(dropdown)
dropdown_select.select_by_value('item3')

# wait for option to become selected
WebDriverWait(browser, 10).until(
    ec.element_selection_state_to_be(
        dropdown_select, True    # how do I 'locate' the option with value 'item3'???
    )
)

Using dropdown_select says expected type 'WebElement', got 'Select' instead. This makes sense, as dropdown_select is, of course, not a locator.

I could use something like the following...

selected_value = (
    dropdown_select
        .first_selected_option
        .get_attribute('value')
)
if selected_value != 'item3':
    raise ValueError('Selected values do not match')

But that's pretty hacky when a method is there for me to use.

How do I define a locator for an option within the Select?

Using xpath relative to the dropdown box, I can create a locator to the option I want like so:

desired_option = dropdown.find_element(
    By.XPATH,
    value='.//option[@value="item3"]'
)

Once I have the locator, I can create the wait, using the element_selection_state_to_be() method:

WebDriverWait(browser, 10).until(
    ec.element_selection_state_to_be(desired_option, True)
)