(abstraction-members)= # Specifying module members The first step in our creation of the backend module is to specify what objects we want to make available for the remote procedure call. You find that workflow in the source code of the backend modules {meth}`~demessaging.backend.module.BackendModule.create_model` method. {ref}`In our example ` we used the `__all__` variable: ```python __all__ = ["hello_world"] ``` In fact, there are two possible ways to specify what should be available for the RPC: 1. using the `__all__` module variable (as we do above). The `__all__` variable is commonly used when using import statements like `from mymodule import *` (see the [python docs](https://docs.python.org/3/tutorial/modules.html#importing-from-a-package)), but it's also a good way to tell other developers about the important functions and methods in your code. 2. The second possibility is specifying the members in the call to the {func}`~demessaging.backend.main` function, e.g. `main(members=["hello_world"])` or `main(members=[hello_world])`. This would then take precedence over the `__all__` variable of the module.