input: Write a function to scrape data from an online web store using Python BeautifulSoup. The function should fetch the raw HTML content from the specified URL, parse it, and extract product names, prices, and descriptions. If the web store URL is not provided, the function should return None.
  assert scrape_web_store(None)==None
  assert scrape_web_store('http://web-store.com')==["Smart Watch $99.99 Stay connected with this smart watch...", "Bluetooth Speaker $49.99 Boost your audio experience...", "Laptop Bag $29.99 Carry your laptop in style..."]
  assert scrape_web_store('http://invalid-url.com')==None
output: def scrape_web_store(url):
      if url is None:
          return None
      try:
          import requests
          from bs4 import BeautifulSoup
          response = requests.get(url)
          if response.status_code != 200:
              return None
          soup = BeautifulSoup(response.content, 'html.parser')
          products = []
          for item in soup.find_all('div', class_='product'):
              name = item.find('h2').text
              price = item.find('span', class_='price').text
              description = item.find('p').text
              products.append(f"{name} {price} {description}")
          return products
      except:
          return None