pub fn as_date(&self) -> crate::Result<Date> {
        match &self {
            Self::Date(d) => Ok(*d),
            _ => Err(error::unimplement("can not convert to Date"))
        }
    }
/// If Value can parse to Date, returns an Date. Returns Err otherwise.
If Value can parse to Date, returns an Date. Returns Err otherwise.
If Value can parse to Date returns an Date . Returns Err otherwise .
pub fn as_date(&self) -> crate::Result<Date> {
        match &self {
            Self::Date(d) => Ok(*d),
            _ => Err(error::unimplement("can not convert to Date"))
        }
    }
pub fn as_date ( & self ) -> crate :: Result < Date > { match & self { Self :: Date ( d ) => Ok ( * d ) , _ => Err ( error :: unimplement ( " " ) ) } }
If Value can parse to Date, returns an Date.
If Value can parse to Date returns an Date .
&self