pub fn deserialize_optional_flags<'de, D, T>(
deserializer: D,
) -> Result<Option<HashSet<T>>, D::Error>where
T: FromStr + Eq + Hash + Deserialize<'de>,
<T as FromStr>::Err: Display,
D: Deserializer<'de>,Expand description
Deserialize null, a string or string sequence into an Option<HashSet<T>>.