in src/main/java/com/twitter/penguin/korean/util/CharArrayMap.java [530:538]
public boolean contains(Object o) {
if (!(o instanceof Map.Entry))
return false;
final Map.Entry<Object, V> e = (Map.Entry<Object, V>) o;
final Object key = e.getKey();
final Object val = e.getValue();
final Object v = get(key);
return v == null ? val == null : v.equals(val);
}