input: Write a python function to retrieve data from a given URL, parse it using BeautifulSoup, and store it in a MongoDB database, then verify the number of records inserted.
  ```python
  import requests
  from bs4 import BeautifulSoup
  import pymongo
  
  def store_data(url, db_name, collection_name):
      # requesting data
      response = requests.get(url)
  
      # parse data
      soup = BeautifulSoup(response.text, 'lxml')
  
      # connect to MongoDB server
      myclient = pymongo.MongoClient("mongodb://localhost:27017/")
  
      # create a MongoDB database
      mydb = myclient[db_name]
  
      # create a collection in the database
      mycol = mydb[collection_name]
  
      # retrieve and store every page's content in the MongoDB database
      for div in soup.find_all('div', class_="box"):
          title = div.h3.text
          description = div.p.text
          data = {
              "title": title,
              "description": description
          }
          mycol.insert_one(data)
  
      return mycol.count_documents({})
  
  # Example usage:
  url = "https://www.example.com"
  db_name = "mydatabase"
  collection_name = "mycollection"
  
  assert store_data(url, db_name, collection_name) == 10  # Adjust the number based on actual records expected
  assert store_data(url, db_name, collection_name) > 0
  assert isinstance(store_data(url, db_name, collection_name), int)
output: return mycol.count_documents({})