One of the appealing features of PyPedal is its easy extensibility. In this section, we will demonstrate how to add a user-written module to PyPedal. The file pyp_template.py that is distributed with PyPedal is a skeleton that can be used to help you get started writing your custom module(s). You should also look at the source code of the standard modules, particularly if there is already a routine that does something similar to what you would like to do, to see if you can jump-start your project by reusing code.