code: public void add(int dimension, float value) {
          if(this.map.containsKey(dimension))
              this.map.put(dimension, this.map.get(dimension) + value);
          else
              this.map.put(dimension, value);
      }
docs: Add a given reward value on a specified dimension.
  
  @param dimension
  the dimension to add the reward on.
  @param value
  the value of the reward.