@return the values view
file : https_github_com_apache_commons-collections_git/src/main/java/org/apache/commons/collections4/map/SingletonMap.java
file : https_github_com_apache_commons-collections_git/src/main/java/org/apache/commons/collections4/map/Flat3Map.java
file : https_github_com_apache_commons-collections_git/src/main/java/org/apache/commons/collections4/map/AbstractHashedMap.java
file : https_github_com_apache_commons-collections_git/src/main/java/org/apache/commons/collections4/bidimap/AbstractDualBidiMap.java