Using Python & Selenium to send message to friend in Facebook

I am currently writing a script in Python to log in on facebook and I want to send message to a friend. The script logs in to my facebook, and it manages to find my friend, but the message is not sent! Im not sure but the problem is the div tag/CSS on the text area(I commented over that piece of code), but still im not 100% if the problem is there, but i think it is..

Here is my code:

from selenium import webdriver
from selenium.webdriver.common.keys import Keys

driver = webdriver.Chrome('C:\path\chromedriver.exe')
driver.get('https://www.facebook.com/')

username_box = driver.find_element_by_id('email')
username_box.send_keys(USEREMAIL)
passElem = driver.find_element_by_id("pass")
passElem.send_keys(USERPASSWORD)
passElem.send_keys(Keys.RETURN)
userTargetUrl = "https://www.facebook.com/messages/t/" + "USERTAGET"
driver.get(userTargetUrl)

//The problem is here I think
    elem = driver.find_element_by_css_selector("div textarea.uiTextareaNoResize")


    while True:
        elem.send_keys("Test")
        elem.send_keys(Keys.RETURN)
        driver.find_element_by_id("u_0_t").click()

The error code i get is:

selenium.common.exceptions.NoSuchElementException: Message: no such element: Unable to locate element: {"method":"css selector","selector":"div textarea.uiTextareaNoResize"} (Session info: chrome=63.0.3239.132) (Driver info: chromedriver=2.35.528161 (5b82f2d2aae0ca24b877009200ced9065a772e73),platform=Windows NT 10.0.15063 x86_64)

Someone plz help?