Python selenium click image button

the html is below:

python is

driver.find_element_by_xpath["//img[contains[@src='resources/images/logout.png']]/parent::a"].click[]

it giving error as below

   driver.find_element_by_xpath["//img[contains[@src='resources/images/logout.png']]/parent::a"].click[]
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 221, in find_element_by_xpath
    return self.find_element[by=By.XPATH, value=xpath]
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 681, in find_element
    {'using': by, 'value': value}]['value']
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 164, in execute
    self.error_handler.check_response[response]
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/errorhandler.py", line 164, in check_response
    raise exception_class[message, screen, stacktrace]
NoSuchElementException: Message: u'Unable to locate element: {"method":"xpath","selector":"//img[contains[@src=\'resources/images/logout.png\']]/parent::a"}' ; Stacktrace: 
    at FirefoxDriver.prototype.findElementInternal_ [file:///tmp/tmpu3t8lf/extensions//components/driver_component.js:8860]
    at fxdriver.Timer.prototype.setTimeout/