Add very basic nested operations example

Author: Fizzadar

snippets/inventory-functions/README.md

@@ -1,6 +1,6 @@
 # Example: Inventory Functions
 
-Like operations inventories can also be defined using Python functions. This brings incredible flexibility allowing you to pull data from external systems using Python's package ecosystem to generate pyinfra inventories. The `inventory.py` contains a triaival example of this which can be executed like so:
+Like operations inventories can also be defined using Python functions. This brings incredible flexibility allowing you to pull data from external systems using Python's package ecosystem to generate pyinfra inventories. The `inventory.py` contains an example of this which can be executed like so:
 
 ```sh
 pyinfra inventory.make_docker_inventory exec uptime

snippets/nested-operations/README.md

@@ -0,0 +1,3 @@
+# Example: Nested Operations
+
+Operations within a `python.call` function are called nested operations. These execute immediately, unlike top-level operations which are collected during the planning phase and executed later. The `nested_ops.py` file contains a very simple example of this.

snippets/nested-operations/nested_ops.py

@@ -0,0 +1,15 @@
+import requests
+from pyinfra.operations import apt, python, server
+
+# Install some service X...
+apt.packages(...)
+
+
+def register_device():
+    get_idx = server.shell(commands="get identifier from service X")
+
+    # Save the service X identifier in some external system
+    requests.post("", get_idx.stdout)
+
+
+python.call(function=register_device)