public void putAll(Map<? extends K, ? extends Integer> t) {
        for (Entry<? extends K, ? extends Integer> entry : t.entrySet()) {
            put(entry.getKey(), entry.getValue());
        }
    }
Remove a key-weight association from this set.

@param key the key to remove
@return the weight that was previously associated with this key, or null (if there was no previous key)
document/src/main/java/com/yahoo/document/datatypes/WeightedSet.java