How to remove the error 'no such element exception' from the below Python code

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Python

selenium

I am trying to run the following code:
from selenium import webdriver
# create a new Firefox session
driver = webdriver.Firefox(executable_path=r'C:\Program Files\geckodriver.exe')
driver.implicitly_wait(30)
driver.maximize_window()
# navigate to the application home page
driver.get("http://demo.magentocommerce.com/")
# get the search textbox
search_field = driver.find_element_by_name("q")
search_field.clear()
# enter search keyword and submit
search_field.send_keys("phones")
search_field.submit()
# get all the anchor elements which have product names displayed
# currently on result page using find_elements_by_xpath method
products = driver.find_elements_by_xpath("//h2[@class=‘productname’]/a")
# get the number of anchor elements found
print ("Found" + str(len(products)) + "products:")
# iterate through each anchor element and print the text that is # name of the product
for product in products:
print (product.text)
# close the browser window

driver.quit()

What I have tried:

But, getting the following errors:
Traceback (most recent call last):
File "C:/Users/nava.malakar/PycharmProjects/setests/searchproducts.py", line 12, in <module>
search_field = driver.find_element_by_name("q")
File "C:\Users\nava.malakar\PycharmProjects\setests\venv\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 487, in find_element_by_name
return self.find_element(by=By.NAME, value=name)
File "C:\Users\nava.malakar\PycharmProjects\setests\venv\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 955, in find_element
'value': value})['value']
File "C:\Users\nava.malakar\PycharmProjects\setests\venv\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 312, in execute
self.error_handler.check_response(response)
File "C:\Users\nava.malakar\PycharmProjects\setests\venv\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 242, in check_response
raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.NoSuchElementException: Message: Unable to locate element: [name="q"]


Process finished with exit code 1


- Updated the geckodriver path in the environment variables also, but still i am getting all these errros and not able to run the program