code: public JobRequest addParameter(String key, String value)
      {
          validateParameter(key, value);
          parameters.put(key, value);
          return this;
      }
docs: Parameters are <key,value> pairs that are passed at runtime to the job. The amount of required parameters depends on the requested
  job itself.
  
  @param key
  max length is 50
  @param value
  max length is 1000