src/main/java/eu/digitisation/math/Counter.java
public Counter<Type> add(Counter<Type> counter) {
        for (Map.Entry<Type, Integer> entry : counter.entrySet()) {
            add(entry.getKey(), entry.getValue());
        }
        return this;
    }
/**
     * Increment the count for an object with the value stored in another
     * counter.
     *
     * @param counter the counter whose values will be added to this one.
     * @return this Counter
     */
Increment the count for an object with the value stored in another
counter.

@param counter the counter whose values will be added to this one.
@return this Counter
Increment the count for an object with the value stored in another counter . @param counter the counter whose values will be added to this one . @return this Counter
public Counter<Type> add(Counter<Type> counter) {
        for (Map.Entry<Type, Integer> entry : counter.entrySet()) {
            add(entry.getKey(), entry.getValue());
        }
        return this;
    }
public Counter < Type > add ( Counter < Type > counter ) { for ( Map . Entry < Type , Integer > entry : counter . entrySet ( ) ) { add ( entry . getKey ( ) , entry . getValue ( ) ) ; } return this ; }
Increment the count for an object with the value stored in another
 counter.
Increment the count for an object with the value stored in another counter .