title: NoSuchElementException: Message: Unable to locate element: {"method":"link text","selector":"Sign in"}
body: <p><strong>I exported Selenium IDE to Python WebDriver and when I run it. I get this error: Something wrong with exception or Sign in id. 
  NoSuchElementException: Message: Unable to locate element: {"method":"link text","selector":"Sign in"}</strong> </p>
  
  <pre><code>from selenium import webdriver
  from selenium.webdriver.common.by import By
  from selenium.webdriver.common.keys import Keys
  from selenium.webdriver.support.ui import Select
  from selenium.common.exceptions import NoSuchElementException
  from selenium.common.exceptions import NoAlertPresentException
  import unittest, time, re
  
  class Vova(unittest.TestCase):
      def setUp(self):
          self.driver = webdriver.Firefox()
          self.driver.implicitly_wait(30)
          self.base_url = `"https://www.yahoo.com/`"
          self.verificationErrors = []
          self.accept_next_alert = True
  
      def test_vova(self):
          driver = self.driver
          driver.get("https://uk.yahoo.com")
          driver.find_element_by_link_text("Mail").click()
          driver.find_element_by_link_text("Sign in").click()
          driver.find_element_by_id("login-username").clear()
          driver.find_element_by_id("login-username").send_keys("")
          driver.find_element_by_id("passwd-field").clear()
          driver.find_element_by_id("passwd-field").send_keys("")
  
      def is_element_present(self, how, what):
          try: self.driver.find_element(by=how, value=what)
          except NoSuchElementException as e: return False
          return True
  
      def is_alert_present(self):
          try: self.driver.switch_to_alert()
          except NoAlertPresentException as e: return False
          return True
  
      def close_alert_and_get_its_text(self):
          try:
              alert = self.driver.switch_to_alert()
              alert_text = alert.text
              if self.accept_next_alert:
                  alert.accept()
              else:
                  alert.dismiss()
              return alert_text
          finally: self.accept_next_alert = True
  
      def tearDown(self):
          self.driver.quit()
          self.assertEqual([], self.verificationErrors)
  
  if __name__ == "__main__":
      unittest.main()
  </code></pre>