How do I use Selenium's wait?

Question

I'm having trouble on figuring out how to use Selenium's wait function. What I'm trying to do is check to see if a element is present and if it is then it'll print a statement. Here is my code:

from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.common.exceptions import TimeoutException

browser = webdriver.Firefox()
browser.get("http://google.com")
delay = 3 # seconds
try:
    WebDriverWait(browser, delay).until(EC.presence_of_element_located(browser.find_element_by_xpath('//*[@id="hplogo"]')))
    print ("Page is ready!")
except TimeoutException:
    print ("Loading took too much time!")

The current code gives me the following errors:

Traceback (most recent call last):
  File "/Users/John/Documents/waitTest.py", line 10, in <module>
    WebDriverWait(browser, delay).until(EC.presence_of_element_located(browser.find_element_by_xpath('//*[@id="hplogo"]')))
  File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/selenium/webdriver/support/wait.py", line 71, in until
    value = method(self._driver)
  File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/selenium/webdriver/support/expected_conditions.py", line 59, in __call__
    return _find_element(driver, self.locator)
  File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/selenium/webdriver/support/expected_conditions.py", line 274, in _find_element
    return driver.find_element(*by)
TypeError: find_element() argument after * must be a sequence, not WebElement

Answer 1

you need to import the By module

from selenium.webdriver.common.by import By

Answer 2

Expected condition expects a tuple to be passed in where the first item is the locator's type (By constant) and the second is the locator's value:

from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC    

wait = WebDriverWait(browser, 10)
wait.until(EC.presence_of_element_located((By.XPATH, '//*[@id="hplogo"]')))

Note that in your case By.ID would be simpler:

wait.until(EC.presence_of_element_located((By.ID, 'hplogo')))