chore: import upstream snapshot with attribution

doc/source/ray-core/doc_code/nested-tasks.py

@@ -0,0 +1,42 @@
+# flake8: noqa
+
+# __nested_start__
+import ray
+
+
+@ray.remote
+def f():
+    return 1
+
+
+@ray.remote
+def g():
+    # Call f 4 times and return the resulting object refs.
+    return [f.remote() for _ in range(4)]
+
+
+@ray.remote
+def h():
+    # Call f 4 times, block until those 4 tasks finish,
+    # retrieve the results, and return the values.
+    return ray.get([f.remote() for _ in range(4)])
+
+
+# __nested_end__
+
+ray.init(num_cpus=4, num_gpus=1)
+
+obj_refs = ray.get(g.remote())
+assert len(obj_refs) == 4
+assert all(isinstance(o, ray.ObjectRef) for o in obj_refs)
+
+
+# __yield_start__
+@ray.remote(num_cpus=1, num_gpus=1)
+def g():
+    return ray.get(f.remote())
+
+
+# __yield_end__
+
+assert ray.get(g.remote()) == 1