code: function(state0, action0, reward0, state1) {
      this.state0 = state0;
      this.action0 = action0;
      this.reward0 = reward0;
      this.state1 = state1;
    }
docs: An agent is in state0 and does action0 environment then assigns reward0 and provides new state, state1 Experience nodes store all this information, which is used in the Q-learning update step