Not loading firefox on selenium webdriver

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/webdriver.py", line 148, in __init__
    self.service.start()
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/common/service.py", line 81, in start
    os.path.basename(self.path), self.start_error_message)
selenium.common.exceptions.WebDriverException: Message: 'geckodriver' executable needs to be in PATH. 

Everything is installed. When i type firefox in terminal, it perfectly opens firefox browser. Help me!!

Answer

FirefoxDriver for Selenium has been discontinued. You must use MarionetteDriver/geckodriver.