Ansible intends to allow users to write modules in any language. Writing the module in Python, however, has its own advantages. You can take advantage of Ansible's libraries to shorten your code, an advantage not available for modules in other languages. Parsing user arguments, handling errors, and returning the required values becomes easier with the help of the Ansible libraries.
We will see two examples for a custom Python module, one with and one without using the Ansible library, to give you a glimpse of how custom modules work. Make sure you organize your directory structure as mentioned in the previous section before creating the module. The first example creates a module named check_user; let's look at the code in the following screenshot:
The preceding custom module, check_user, will check whether a user exists on a host. The module expects a user argument from Ansible. Let's break down the preceding module and see what it does.