Implement a fixed function that calculates only the simple moving average with a predefined window size, ensuring simplicity and quick deployment.

Develop a function that exclusively calculates the exponential moving average using a default decay factor, optimizing for performance with large datasets.

Create a comprehensive function that computes both simple and exponential moving averages with fixed parameters, offering users a choice between two predefined methods.

Design a customizable function that allows users to specify the type of moving average (simple or exponential) and its parameters (window size or decay factor), providing flexibility and adaptability to various scenarios.