Uname:    "david",
			Gname:    "david",
			Devmajor: 0,
			Devminor: 0,
			PAXRecords: map[string]string{
				"GNU.sparse.major":    "1",
				"GNU.sparse.minor":    "0",
				"GNU.sparse.realsize": "200",
				"GNU.sparse.name":     "sparse-posix-1.0",
			},
			Format: FormatPAX,
		}, {
			Name:     "end",
			Mode:     420,
			Uid:      1000,
			Gid:      1000,
			Size:     4,

So, in our example, we can make `tags` be specifically a "list of strings":

{* ../../docs_src/body_nested_models/tutorial002_py310.py hl[12] *}

## Set types { #set-types }

But then we think about it, and realize that tags shouldn't repeat, they would probably be unique strings.

And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

```Python hl_lines="3  5-6"
{
    "name": "Baz",
    "description": None,
    "price": 50.2,
    "tax": 10.5,
    "tags": []
}
```

FastAPI is smart enough (actually, Pydantic is smart enough) to realize that, even though `description`, `tax`, and `tags` have the same values as the defaults, they were set explicitly (instead of taken from the defaults).

So, they will be included in the JSON response.

/// tip