<system>
You are an experienced Python developer. You will be provided with an incorrect code snippet from a Python program. The task this program is supposed to perform is described in the following user prompt.
Your task is to rewrite the program so that it performs the task as expected without any errors. You will be rewarded based on the number of test cases your code passes.
</system>

<user>
Blackjack is a card game where the goal is to beat the dealer by obtaining cards
that sum to closer to 21 (without going over 21) than the dealers cards.

## Description
The game starts with the dealer having one face up and one face down card,
while the player has two face up cards. All cards are drawn from an infinite deck
(i.e. with replacement).

The card values are:
- Face cards (Jack, Queen, King) have a point value of 10.
- Aces can either count as 11 (called a 'usable ace') or 1.
- Numerical cards (2-9) have a value equal to their number.

The player has the sum of cards held. The player can request
additional cards (hit) until they decide to stop (stick) or exceed 21 (bust,
immediate loss).

After the player sticks, the dealer reveals their facedown card, and draws cards
until their sum is 17 or greater. If the dealer goes bust, the player wins.

If neither the player nor the dealer busts, the outcome (win, lose, draw) is
decided by whose sum is closer to 21.

## Action Space
The action shape is `(1,)` in the range `{0, 1}` indicating
whether to stick or hit.

- 0: Stick
- 1: Hit

## Observation Space
The observation consists of a 3-tuple containing: the player's current sum,
the value of the dealer's one showing card (1-10 where 1 is ace),
and whether the player holds a usable ace (0 or 1).

The observation is returned as `(int(), int(), int())`.

## Starting State
The starting state is initialised in the following range.

| Observation               | Min  | Max  |
|---------------------------|------|------|
| Player current sum        |  4   |  12  |
| Dealer showing card value |  2   |  11  |
| Usable Ace                |  0   |  1   |

## Rewards
- win game: +1
- lose game: -1
- draw game: 0
- win game with natural blackjack:
+1.5 (if <a href="#nat">natural</a> is True)
+1 (if <a href="#nat">natural</a> is False)

## Episode End
The episode ends if the following happens:

- Termination:
1. The player hits and the sum of hand exceeds 21.
2. The player sticks.

An ace will always be counted as usable (11) unless it busts the player.

## Class Definition
The class should be called "Environment". It should have at least:

- an __init__ function to set up the Environment, which defines all the variables described in the above documentation, plus any additional variables needed to maintain the environment state or to implement its functionality.
- a set_state function to set a custom value for the environment and its internal representation (you can assume that when "set_state" is used, the task is not done and internal variables should be set as a consequence). set_state takes a single argument as input: a state observation from the observation space defined above.
- a step function to predict a step in the environment. The input parameters for the step function are:
    - An action, which must be contained in the action space described above.
  
    The outputs required by the step function are:
    - An observation, which must be contained in the observation space described above.
    - The reward for taking the action, as described in the reward definition above.
    - A boolean variable indicating if the episode is done.

## Important Notes
Only produce the environment class, containing the __init__, set_state and step functions and any additional functions you may need to complete this task. Do not write an example of how to use the class or anything else.
Be careful about edge cases.
Make sure to write all the required functions and that they have the exact names as specified in the task description. Missing or incorrectly named functions will not pass the tests and will result in a score of 0.
It is of VITAL importance that you do not leave undefined any function, but implement each of them completely.

First, write an explanation of the difference between the ground-truth transition and the step function's outputs in the example provided.
Second, point out the part of the code responsible for the incorrect prediction and why its logic is erroneous.
Third, suggest a concrete, actionable fix for it. 
Finally, fix the program in its entirety following the suggestion. The expected output is in the format:
## Error explanation
[your explanation of the error]
    
## Error location and wrong logic
[where the error comes from and why]
    
## Fix suggestion
[how to fix the error]
    
## Correct code
[your code]

## Incorrect code
You are provided with the following code snippet to fix.
```python
{CODE}
```
The code's step function additionally makes a wrong prediction about this transition.
## Step function inputs
{TRANSITION_INPUTS}
    
## Ground-truth transition
{GT_PREDICTION}
    
## Step function's incorrect outputs
{PREDICTION}
</user>