In some cases you don't really need the return value of a dependency inside your *path operation function*. Or the dependency doesn't return a value. But you still need it to be executed/solved. For those cases, instead of declaring a *path operation function* parameter with `Depends`, you can add a `list` of `dependencies` to the *path operation decorator*. ## Add `dependencies` to the *path operation decorator* The *path operation decorator* receives an optional argument `dependencies`. It should be a `list` of `Depends()`: ```Python hl_lines="17" {!./src/dependencies/tutorial006.py!} ``` These dependencies will be executed/solved the same way normal dependencies. But their value (if they return any) won't be passed to your *path operation function*. !!! tip Some editors check for unused function parameters, and show them as errors. Using these `dependencies` in the *path operation decorator* you can make sure they are executed while avoiding editor/tooling errors. It might also help avoiding confusion for new developers that see an un-used parameter in your code and could think it's unnecessary. ## Dependencies errors and return values You can use the same dependency *functions* you use normally. ### Dependency requirements They can declare request requirements (like headers) or other sub-dependencies: ```Python hl_lines="6 11" {!./src/dependencies/tutorial006.py!} ``` ### Raise exceptions These dependencies can `raise` exceptions, the same as normal dependencies: ```Python hl_lines="8 13" {!./src/dependencies/tutorial006.py!} ``` ### Return values And they can return values or not, the values won't be used. So, you can re-use a normal dependency (that returns a value) you already use somewhere else, and even though the value won't be used, the dependency will be executed: ```Python hl_lines="9 14" {!./src/dependencies/tutorial006.py!} ``` ## Dependencies for a group of *path operations* Later, when reading about how to structure bigger applications, possibly with multiple files, you will learn how to declare a single `dependencies` parameter for a group of *path operations*.