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/// A module that deserializes `[]` optionally
pub mod empty_params {
    use serde::{Deserialize, Deserializer};

    pub fn deserialize<'de, D>(d: D) -> Result<(), D::Error>
    where
        D: Deserializer<'de>,
    {
        let seq = Option::<Vec<()>>::deserialize(d)?.unwrap_or_default();
        if !seq.is_empty() {
            return Err(serde::de::Error::custom(format!(
                "expected params sequence with length 0 but got {}",
                seq.len()
            )));
        }
        Ok(())
    }
}