input: Write a python function to filter courses by topic, language, and price range.
  assert filter_courses(courses, "Web Development", "Python", 60) == [{"id":1, "topic":"Web Development", "language":"Python","price":50}]
  assert filter_courses(courses, "AI & ML", "R", 150) == [{"id":2, "topic":"AI & ML", "language":"R","price":150}]
  assert filter_courses(courses, "Data Science", "Python", 50) == []
  assert filter_courses(courses, "Machine Learning", "Python", 250) == [{"id":4, "topic":"Machine Learning", "language":"Python","price":200}]
output: def filter_courses(courses, topic, language, max_price):
      return [
          course for course in courses
          if course['topic'] == topic and course['language'] == language and course['price'] <= max_price
      ]