✨ Add docs and tests for Python 3.9 and Python 3.10 (#3712)

Co-authored-by: Thomas Grainger <tagrain@gmail.com>

docs_src/query_params/tutorial002_py310.py

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+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/items/{item_id}")
+async def read_item(item_id: str, q: str | None = None):
+    if q:
+        return {"item_id": item_id, "q": q}
+    return {"item_id": item_id}

docs_src/query_params/tutorial003_py310.py

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+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/items/{item_id}")
+async def read_item(item_id: str, q: str | None = None, short: bool = False):
+    item = {"item_id": item_id}
+    if q:
+        item.update({"q": q})
+    if not short:
+        item.update(
+            {"description": "This is an amazing item that has a long description"}
+        )
+    return item

docs_src/query_params/tutorial004_py310.py

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+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/users/{user_id}/items/{item_id}")
+async def read_user_item(
+    user_id: int, item_id: str, q: str | None = None, short: bool = False
+):
+    item = {"item_id": item_id, "owner_id": user_id}
+    if q:
+        item.update({"q": q})
+    if not short:
+        item.update(
+            {"description": "This is an amazing item that has a long description"}
+        )
+    return item

docs_src/query_params/tutorial006_py310.py

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+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/items/{item_id}")
+async def read_user_item(
+    item_id: str, needy: str, skip: int = 0, limit: int | None = None
+):
+    item = {"item_id": item_id, "needy": needy, "skip": skip, "limit": limit}
+    return item

docs_src/query_params/tutorial006b.py

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+from typing import Union
+
+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/items/{item_id}")
+async def read_user_item(
+    item_id: str, needy: str, skip: int = 0, limit: Union[int, None] = None
+):
+    item = {"item_id": item_id, "needy": needy, "skip": skip, "limit": limit}
+    return item