What will happen if one of the positional arguments is not specified? Let's look at the example:

An error occurred when we forgot to specify some of the positional arguments. In real projects, this behavior is unacceptable, as it generates a lot of bugs and badly affects the system's fault tolerance. One solution to this problem is to use optional arguments.
In Python, optional arguments are positional function arguments with a predefined default value assigned to them. We can use the following syntax:

These arguments are optional when calling the function, as the default value will be used if no value is specified for that argument.

To define an optional argument, you can assign a default value to the corresponding parameter in the function definition. Here's an example:

But there is one important rule when using optional arguments - they must be specified after all non-optional arguments. If this rule is not met, the error will occur.