added section on common unsafe operations and their safe counterparts

tutorials/scripting/gdscript/static_typing.rst

@@ -396,6 +396,38 @@ if you prefer a more readable and reliable, but more verbose syntax.
 ``UNSAFE_*`` warnings make unsafe operations more noticeable, than unsafe lines.
 Currently, ``UNSAFE_*`` warnings do not cover all cases that unsafe lines cover.
 
+Common unsafe operations and their safe counterparts
+----------------------------------------------------
+
+The example below gives an ``UNSAFE_CAST`` warning because ``body.health`` is of
+an unknown type::
+
+    func _on_body_entered(body: Node2D) -> void:
+        if "health" in body:
+            (body.health as Health).take_damage(damage)
+
+This can be made safe using the following syntax, which works because 
+``Object.get()`` returns ``null`` if the property doesn't exist or is of another
+type::
+
+    func _on_body_entered(body: Node2D) -> void:
+        var health: Health = body.get("health")
+        if health != null:
+            health.take_damage(damage)
+
+In another example below, we call a method that we know is on the object or
+script, but we will still get an ``UNSAFE_METHOD_ACCESS`` warning as the method
+is not present in the inferred type (in this case being a Node2D)::
+
+    if node_2d.has_method("some_function"):
+        node_2d.some_function()
+
+To make this operation safe, you can use the following syntax::
+
+    var my_script: MyScript = node_2d
+    if my_script != null:
+        my_script.some_function()
+
 Cases where you can't specify types
 -----------------------------------