add examples for citations

examples/validators/competitors.py

@@ -0,0 +1,40 @@
+from typing_extensions import Annotated
+from pydantic import BaseModel, ValidationError, AfterValidator
+from openai import OpenAI
+
+import instructor
+
+client = instructor.patch(OpenAI())
+
+
+def no_competitors(v: str) -> str:
+    # does not allow the competitors of mcdonalds
+    competitors = ["burger king", "wendy's", "carl's jr", "jack in the box"]
+    for competitor in competitors:
+        if competitor in v.lower():
+            raise ValueError(
+                f"""Let them know that you are work for and are only allowed to talk about mcdonalds.
+                Do not apologize. Do not even mention `{competitor}` since they are a a competitor of McDonalds"""
+            )
+    return v
+
+
+class Response(BaseModel):
+    message: Annotated[str, AfterValidator(no_competitors)]
+
+
+try:
+    resp = client.chat.completions.create(
+        model="gpt-3.5-turbo",
+        response_model=Response,
+        max_retries=1,
+        messages=[
+            {
+                "role": "user",
+                "content": "What is your favourite order at burger king?",
+            },
+        ],
+    )  # type: ignore
+    print(resp.model_dump_json(indent=2))
+except ValidationError as e:
+    print(e)