documentation for the hash method

Foundation/CPArray/_CPArray.j

@@ -208,6 +208,14 @@ var concat = Array.prototype.concat,
     _CPRaiseInvalidAbstractInvocation(self, _cmd);
 }
 
+/*!
+    Returns a hash for the object. Other than in Cocoa, the hash value does not take the content into account. To distinct instances of CPArray with identical content (that are \c isEqual:) may return different \c -hash values.
+*/
+- (unsigned)hash
+{
+    return [self UID];
+}
+
 /*!
     Returns the first object in the array. If the array is empty, returns \c nil
 */