 
   @inlinable
   @inline(__always)
+  func contains(_ key: Key) -> Bool {
+    return find(key).found
+  }
+
+  @inlinable
+  @inline(__always)
   func lookup(_ index: Index) -> (key: Key, value: Value) {
     _precondition(hashTable.isOccupied(index),
       "Attempting to access Dictionary elements using an invalid Index")

        return cocoa.count
#endif
      }
    }
  }


  func index(forKey key: Key) -> Index?
  var count: Int { get }

  func contains(_ key: Key) -> Bool
  func lookup(_ index: Index) -> (key: Key, value: Value)
  func lookup(_ key: Key) -> Value?
}
