Explain the purpose and usage of the yield keyword in Python. How does it relate to generators?

The yield keyword is used in Python to create generator functions. It allows you to pause the function's execution and yield a value back to the caller, while retaining the state of the function. Generators are iterators that lazily produce values on-the-fly, making them memory-efficient for handling large datasets or infinite sequences. Each time the generator's next() method is called, it resumes execution from where it left off.