MoseleyBioinformaticsLab/jpredapi ? reverse-engineered prompt

Build me a small Python package and command line tool for working with JPred, the protein secondary structure prediction service.

I want it to let me submit a protein sequence or file, track the job, and then fetch the results when they are ready. It should be easy to use both as a library from Python and from the terminal. Please include a simple command line interface with clear help text, sensible error messages, and support for the basic submit and retrieve flow.

Make it feel like a real installable package, with tests and basic documentation or examples so someone can understand how to use it quickly. If you need to check the latest JPred API details or behavior, look up the current docs online.

Keep it lightweight and practical, focused on the common workflow of sending jobs to JPred and getting the prediction output back.