code: public V put(Character key, V value) {
  	char k = checkKey(key);
          return put(k, value);
      }
docs: Adds the mapping from the provided key to the value.
  
  @param key
  @param value
  
  @throws NullPointerException if the key is {@code null}
  @throws IllegalArgumentException if the key is not an instance of {@link
  Integer}