input: Write a function named `create_web_scraper` that creates a web scraper using Python’s Selenium to retrieve data from an online store. The function should initialize a Firefox driver, navigate to a specified URL, perform a search, and print out the names of the products found. If no products are found, it should print an appropriate message.
  assert create_web_scraper("https://www.example.com/", "shoes")==None
  assert create_web_scraper("https://www.example.com/", "non-existent-item")==None
  assert create_web_scraper("https://www.example.com/", "")==None
  assert create_web_scraper("https://www.example.com/", "shirts")==None
output: def create_web_scraper(url, search_term):
      from selenium import webdriver
      from selenium.webdriver.common.by import By
      from selenium.webdriver.firefox.service import Service
      from selenium.webdriver.firefox.options import Options
      from selenium.webdriver.common.keys import Keys
      import time
  
      options = Options()
      options.add_argument('-headless')
      service = Service('/path/to/geckodriver')
      driver = webdriver.Firefox(service=service, options=options)
  
      driver.get(url)
      search_box = driver.find_element(By.NAME, "q")
      search_box.send_keys(search_term)
      search_box.send_keys(Keys.RETURN)
  
      time.sleep(5)
  
      try:
          products = driver.find_elements(By.CLASS_NAME, "product-name")
          if products:
              for product in products:
                  print(product.text)
          else:
              print("No products found.")
      except:
          print("No products found.")
  
      driver.quit()