fn contains<Q: ?Sized>(&self, key: &Q) -> bool
    where
        K: Borrow<Q>,
        Q: Eq,
    {
        match self.get(key) {
            Some(_) => true,
            None => false,
        }
    }
/// Returns true if this container contains the key.
Returns true if this container contains the key.
Returns true if this container contains the key .
fn contains<Q: ?Sized>(&self, key: &Q) -> bool
    where
        K: Borrow<Q>,
        Q: Eq,
    {
        match self.get(key) {
            Some(_) => true,
            None => false,
        }
    }
fn contains < Q : ? Sized > ( & self , key : & Q ) -> bool where K : Borrow < Q > , Q : Eq , { match self . get ( key ) { Some ( _ ) => true , None => false , } }
Returns true if this container contains the key.
Returns true if this container contains the key .
&self
key
&Q