Function ruma_serde::int_or_string_to_int

pub fn int_or_string_to_int<'de, D>(de: D) -> Result<Int, D::Error> where
    D: Deserializer<'de>, 

Take either an integer number or a string and deserialize to an integer number.

To be used like this: #[serde(deserialize_with = "int_or_string_to_int")]