title: python selenium webscraping "NoSuchElementException" not recognized
body: <p>Sometimes on a page I'll be looking for an element which may or may not be there. I wanted to try/catch this case with a <code>NoSuchElementException</code>, which selenium was throwing when certain HTML elements didn't exist. Original exception:</p>
  
  <pre><code>NoSuchElementException: Message: u'Unable to locate element: {"method":"css selector","selector":"#one"}' ; Stacktrace: 
      at FirefoxDriver.prototype.findElementInternal_ (file:///var/folders/6q/7xcjtgyj32nfc2yp_y5tr9pm0000gn/T/tmp63Mz2a/extensions/fxdriver@googlecode.com/components/driver_component.js:8899)
      at FirefoxDriver.prototype.findChildElement (file:///var/folders/6q/7xcjtgyj32nfc2yp_y5tr9pm0000gn/T/tmp63Mz2a/extensions/fxdriver@googlecode.com/components/driver_component.js:8911)
      at DelayedCommand.prototype.executeInternal_/h (file:///var/folders/6q/7xcjtgyj32nfc2yp_y5tr9pm0000gn/T/tmp63Mz2a/extensions/fxdriver@googlecode.com/components/command_processor.js:10840)
      at DelayedCommand.prototype.executeInternal_ (file:///var/folders/6q/7xcjtgyj32nfc2yp_y5tr9pm0000gn/T/tmp63Mz2a/extensions/fxdriver@googlecode.com/components/command_processor.js:10845)
      at DelayedCommand.prototype.execute/&lt; (file:///var/folders/6q/7xcjtgyj32nfc2yp_y5tr9pm0000gn/T/tmp63Mz2a/extensions/fxdriver@googlecode.com/components/command_processor.js:10787) 
  </code></pre>
  
  <p>Ironically, it won't let me catch this exception which it was throwing before? Code here:</p>
  
  <pre><code>elt = driver.find_element_by_css_selector('.information')
  try:
      dat1 = elt.find_element_by_css_selector('#one').text
      dat2 = elt.find_elements_by_css_selector('#two')[1].text
      text = dat1 + dat2
  except NoSuchElementException:
      text = elt.find_element_by_css_selector('#all').text
      item.set_description(text)
  </code></pre>
  
  <p>Error here:</p>
  
  <pre><code>NameError: name 'NoSuchElementException' is not defined
  </code></pre>
  
  <p>Googling/documentation came up with nothing...and it strikes me as strange that selenium is fine throwing an exception but can't catch it. </p>