pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool
        where K: Ord + Borrow<Q>, Q: Ord
    {
        self.get(key).is_some()
    }
/// Returns `true` if the map contains an item corresponding to the key.
Returns `true` if the map contains an item corresponding to the key.
Returns ` true ` if the map contains an item corresponding to the key .
pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool
        where K: Ord + Borrow<Q>, Q: Ord
    {
        self.get(key).is_some()
    }
pub fn contains_key < Q : ? Sized > ( & self , key : & Q ) -> bool where K : Ord + Borrow < Q > , Q : Ord { self . get ( key ) . is_some ( ) }
Returns `true` if the map contains an item corresponding to the key.
Returns ` true ` if the map contains an item corresponding to the key .
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key
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key
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