[
    Function {
        name: Identifier {
            start: (
                1,
                16,
            ),
            name: "foo",
            end: (
                1,
                19,
            ),
        },
        attributes: [],
        params: [
            Param {
                name: Variable {
                    start: (
                        1,
                        37,
                    ),
                    name: "b",
                    end: (
                        1,
                        39,
                    ),
                },
                attributes: [],
                type: Some(
                    Union(
                        [
                            String,
                            Integer,
                            Float,
                        ],
                    ),
                ),
                variadic: false,
                default: None,
                flags: [],
                by_ref: false,
            },
        ],
        body: [],
        return_type: None,
        by_ref: false,
    },
]