Write a python function to apply a markdown rate to certain song streams.

Hard Difficulty

Hard questions require advanced understanding and critical thinking. Here, your problem-solving skills are key, as these questions often involve complex scenarios needing in-depth analysis and well-structured responses.

Coding question

Coding questions assess your programming abilities and thought process. Showcase your problem-solving approach, coding style, knowledge of data structures, and ability to write clean, efficient, and maintainable code.

Here's a Hint

Focus on clean code that handles different rate structures, edge cases, and maintains data integrity while efficiently processing potentially large datasets.