title: unknown error: Unsupported locator strategy: By
body: <p>I am trying to use selenium with python and am running into an issue when trying to use the webdriver.expectedConditions class.</p>
  
  <p>The following code is excerpted from a couple of classes, but all necessary code is included:</p>
  
  <pre><code>from selenium.webdriver.common.by import By
  from selenium.webdriver.support.ui import WebDriverWait
  from selenium.webdriver.support import expected_conditions as EC
  
  def isVisible(self, driver, HOW, WHAT, timeout=2):
      locator=(HOW,WHAT)
      try:
          WebDriverWait(driver, timeout).until(EC.visibility_of_element_located(locator))
          return True
      except TimeoutException:
          return False
  
  newApplicationXpath = "//input[@value='New']"
  self.assertTrue(self.isVisible(self.driver, "By.XPATH",     newApplicationXpath, 120))
  </code></pre>
  
  <p>Traceback:</p>
  
  <blockquote>
    <p>WebDriverException: Message: unknown error: Unsupported locator strategy: By
      (Session info: chrome=66.0.3359.139)
      (Driver info: chromedriver=2.37.544315 (730aa6a5fdba159ac9f4c1e8cbc59bf1b5ce12b7),platform=Linux 4.1.12-112.14.10.el7uek.bug27766149.x86_64 x86_64)</p>
  </blockquote>