/// Returns a reference to this meta item as a `Lit` or `None` if is not a literal.
Returns a reference to this meta item as a `Lit` or `None` if is not a literal.
Returns a reference to this meta item as a ` Lit ` or ` None ` if is not a literal .
pub fn as_literal(&self) -> Option<&Lit> {
        match self {
            MetaItem::Literal(x) => Some(x),
            _ => None,
        }
    }
pub fn as_literal ( & self ) -> Option < & Lit > { match self { MetaItem :: Literal ( x ) => Some ( x ) , _ => None , } }
Returns a reference to this meta item as a `Lit` or `None` if is not a literal.
Returns a reference to this meta item as a ` Lit ` or ` None ` if is not a literal .
&self