diff --git a/zk/Pydantic.md b/zk/Pydantic.md
index 432917c..29d934c 100644
--- a/zk/Pydantic.md
+++ b/zk/Pydantic.md
@@ -52,6 +52,21 @@ class VariantProperties(CommonProperties):
 > Note that the `BaseModel` must "drill-down"; it must be inherited at each
 > stage.
 
+## Transform incoming values (before validation)
+
+In the following example I convert an incoming `str` value to a list of strings:
+
+```py
+class MySchema(BaseModel)
+    sub_genres: Optional[List[str]] = None)
+        @field_validator("sub_genres", mode="before")
+        @classmethod
+        def string_to_list(cls, v):
+            if isinstance(v, str):
+                return [v]
+            return v
+```
+
 ## Aliasing
 
 Sometimes the incoming data that you wish to validate will have field names
diff --git a/zk/Pytest_fixtures.md b/zk/Pytest_fixtures.md
index c9cb8ff..00d5a76 100644
--- a/zk/Pytest_fixtures.md
+++ b/zk/Pytest_fixtures.md
@@ -86,3 +86,7 @@ Then to specify the units that will run as the `yield` we just inject `setup`:
 def some_function(setup_function):
     pass
 ```
+
+## Example: setting up mocks before every test
+
+We can combine the