input: Write a function to scrape movie titles, ratings, dates, and descriptions from a given URL using BeautifulSoup.
  assert scrape_movie_data('https://www.example.com/movies') == {'titles': ['Movie1', 'Movie2'], 'ratings': ['5.0', '4.5'], 'dates': ['2023-01-01', '2023-02-01'], 'descriptions': ['Description1', 'Description2']}
  assert scrape_movie_data('https://www.example.com/othermovies') == {'titles': ['Movie3', 'Movie4'], 'ratings': ['4.0', '3.5'], 'dates': ['2023-03-01', '2023-04-01'], 'descriptions': ['Description3', 'Description4']}
  assert scrape_movie_data('https://www.example.com/nomovies') == {'titles': [], 'ratings': [], 'dates': [], 'descriptions': []}
output: def scrape_movie_data(url):
      import requests
      from bs4 import BeautifulSoup
  
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      
      titles = [title.get_text() for title in soup.select('.movie-title')]
      ratings = [rating.get_text() for rating in soup.select('.movie-rating')]
      dates = [date.get_text() for date in soup.select('.movie-date')]
      descriptions = [description.get_text() for description in soup.select('.movie-description')]
      
      return {'titles': titles, 'ratings': ratings, 'dates': dates, 'descriptions': descriptions}