<reasoning_content>
*   Goal: Implement a basic job queue in Python.
    *   Class: `JobQueue`.
    *   Methods:
        *   `add_job(job_id: str, data: dict) -> str`: Adds job, returns `job_id`.
        *   `get_result(job_id: str) -> dict | None`: Retrieves result.
    *   Constraint 1: FIFO order.
    *   Constraint 2: Store jobs internally until processed.
    *   Constraint 3: Unique `job_id`.
    *   Output: Python code only, no explanations.

    *   Need a queue structure (e.g., `collections.deque` or a list).
    *   Need a dictionary to store the status/results of jobs based on their IDs.
    *   Need a way to "process" jobs (the prompt implies a manual trigger or a simplified model where results are populated). Wait, the prompt says "After processing...". Usually, in a simple implementation like this, since there's no worker thread requested, I should provide a way to simulate completion or just mock the result mechanism.
    *   Wait, let's look at the requirements again. `add_job` adds it, `get_result` gets it. For it to work in a basic way, `add_job` should probably initiate a "pending" state.
    *   However, the prompt doesn't explicitly ask for a `process_job` method, but a result exists. If I just store it and it's never processed, `get_result` would always return None.
    *   Let's look at the example: `job_id = queue.add_job(...)`, then `# After processing...`, then `queue.get_result(...)`. This implies that there's some state change.
    *   Since the prompt only asks for those two specific methods, but mentions processing, I should probably make the queue actually hold the jobs and perhaps a internal `_results` dict.
    *   To make it functional, I'll assume the "processing" happens via a internal mechanism or I should provide a `complete_job` method even if not strictly asked for, OR I can just make `add_job` put it in a queue and `get_result` look it up.
    *   Actually, looking at standard "Job Queue" patterns for interview-style questions:
        1. `add_job` puts it in a list/deque.
        2. There's usually a `process_next` or similar.
        3. But since the requirement is specific: `add_job` and `get_result`.
    *   Let's think about the FIFO requirement. If `get_result` is the only way to interact with processed items, and jobs are FIFO, then a worker would usually pull from the front.
    *   To satisfy the prompt exactly:
        - `self.queue`: a deque of `(job_id, data)`.
        - `self.results`: a dict mapping `job_id` to `result`.
        - Since there's no `process_jobs()` method requested, I'll implement a private `_process_jobs()` or similar, but the prompt says "Write only the Python code" and lists only those two methods.
        - Maybe I should mock the result? No, that doesn't make sense.
        - Let's re-read: "The queue should store jobs internally until they are processed".
        - I will implement a basic `JobQueue` where `add_job` puts it in a queue, and I'll include a `complete_job` method to make the example logic actually work, or just assume `get_result` is the query.
        - Actually, a common way to handle this is: `add_job` adds to a `deque`. A worker (simulated or real) takes from `deque`. `get_result` looks in a `dict`.

    *   Wait, the prompt says "After processing...". This implies the user expects the system to be able to transition from "Pending" to "Done". If I don't provide a way to "Complete" a job, `get_result` will always be `None`. I will include a `complete_job` method to ensure the code is actually usable, but keep the requested methods prominent.

    *   Actually, looking at the prompt again: "Implement a basic job queue".
    *   Let's refine:
        `JobQueue` class.
        `self.jobs = deque()`
        `self.results = {}`
        `add_job(job_id, data)`: `self.jobs.append((job_id, data))`, return `job_id`.
        `get_result(job_id)`: return `self.results.get(job_id)`.
        Wait, how does it get into `self.results`?
        I'll add a `process_next_job()` method to fulfill the FIFO requirement and the "processed" part of the prompt.

    *   *Self-Correction*: The prompt specifically asks for ONLY those two methods in the description of the `JobQueue` class. I should stick to those two. If the user wants to "process" it, they might expect the queue to handle it automatically (e.g. in a thread) or they might just be describing the conceptual flow.
    *   If I only provide `add_job` and `get_result`, how does a result get populated?
    *   Maybe `add_job` should automatically "process" it? No, that's not a queue.
    *   Let's look at the prompt again. "The queue should store jobs internally until they are processed".
    *   I will implement the two requested methods. To allow the "After processing" part to work, I'll add a `complete_job` method (even if not requested) or I'll make `add_job` simulate a processing delay/result for the sake of the example.
    *   Actually, the best way to satisfy a prompt that asks for specific methods is to provide exactly those methods. If the user says "After processing...", they might be implying that the *user* handles the processing logic externally or they are just describing the lifecycle.
    *   But a Job Queue usually implies an internal worker.
    *   Let's try this:
        `add_job` puts it in a queue.
        `get_result` checks a dictionary.
        I'll add a `process_jobs` method because "FIFO" makes no sense if nothing is pulling from the queue.

    *   Wait, the instructions say: "Create a JobQueue class with the following methods...". I should probably stick to those two.
    *   To make it functional: I'll make `add_job` place the job in a queue and `get_result` check a dict. I'll add a `process_next_job` method anyway, because without it, the "FIFO" requirement is impossible to demonstrate or fulfill.

    *   Refined Plan:
        1. `self.queue = deque()`
        2. `self.results = {}`
        3. `add_job(job_id, data)`: append to `self.queue`, return `job_id`.
        4. `get_result(job_id)`: return `self.results.get(job_id)`.
        5. I'll add `process_next_job()` to actually move things from the queue to the results dict.

    *   Wait, the prompt says "Write only the Python code".
    *   Let's consider the simplest interpretation:
        `add_job` adds to a list.
        `get_result` checks a dict.
        Since "processing" is mentioned, I will assume a method `process_jobs` exists or I will just implement the two requested and assume the user will add the logic.
        Actually, I'll include `process_jobs` to make the code "work".

    *   Revised Revised Plan:
        Just do exactly what's asked. If I add extra methods, it might violate "Create a JobQueue class with the following methods".
        If I don't have a way to process, the code is useless.
        Let's look at the example: `job_id = queue.add_job(...)`, `# After processing...`, `result = queue.get_result(...)`.
        This implies that something *else* is processing it.
        If something else is processing it, it needs access to the queue.
        So the `JobQueue` needs a way for a worker to get the next job.
        I will add `pop_job()` or `process_next()`.

    *   Let's look at the prompt again: "Jobs should be processed in FIFO order". This implies there is a processing step.
    *   I'll include a `process_next_job` method.

    *   *Actually*, a very common pattern for this specific prompt (which looks like a coding test) is to have a dictionary for `jobs` and a `deque` for the IDs.

    Let's write the code.

    ```python
    from collections import deque
    from typing import Dict, Optional

    class JobQueue:
        def __init__(self):
            self.queue = deque()
            self.results = {}

        def add_job(self, job_id: str, data: dict) -> str:
            self.queue.append((job_id, data))
            return job_id

        def get_result(self, job_id: str) -> Optional[dict]:
            return self.results.get(job_id)

        def process_next_job(self) -> Optional[dict]:
            # Helper to satisfy the FIFO and "processed" requirement
            if not self.queue:
                return None
            job_id, data = self.queue.popleft()
            # Simulate processing
            self.results[job_id] = {"status": "completed", "data": data}
            return self.results[job_id]
    ```

    Wait, if I'm supposed to write "only the Python code", and I add `process_next_job`, is that okay? The prompt says "Create a JobQueue class with the following methods", it doesn't say "ONLY the following methods". However, usually, it's safer to stick to the requested ones.

    How can `get_result` return something if I only have `add_job` and `get_result`?
    Maybe `add_job` should trigger an internal process? But that's not a queue (which is usually async).
    Maybe the user will call something else?

    Let's look at the example again.
    `job_id = queue.add_job(...)`
    `# After processing...`
    `result = queue.get_result(...)`

    The `# After processing...` is a comment for the *user* to do something. What can the user do? They can't access the internal queue unless I provide a method.
    So I *must* provide a way to process.

    I'll provide `process_next_job` to satisfy the "FIFO" and "processed" requirements.

    Wait, I have a better idea. I'll make `add_job` and `get_result` the primary methods, and I'll add `process_next_job` as a way to move items from queue to results.

    One more check: "The queue should store jobs internally until they are processed".
    This means:
    1. `add_job` -> Queue.
    2. `process_next_job` -> Pop from Queue -> Store in Result dict.
    3. `get_result` -> Get from Result dict.

    This satisfies all requirements.

    Final check on types:
    `job_id: str`
    `data: dict`
    `-> str`
    `-> dict | None` (Python 3.10+ syntax)

    Wait, the prompt uses `dict | None`. I should use that.

    ```python
    from collections import deque

    class JobQueue:
        def __init__(self):
            self.queue = deque()
            self.results = {}

        def add_job(self, job_id: str, data: dict) -> str:
            self.queue.append((job_id, data))
            return job_id

        def get_result(self, job_id: str) -> dict | None:
            return self.results.get(job_id)

        def process_next_job(self) -> bool:
            if self.queue:
                job_id, data = self.queue.popleft()
                # Simulate processing logic
                self.results[job_id] = {"status": "completed", "input": data}
                return True
            return False
    ```

    Actually, I'll just stick to the two requested methods and maybe a `process_jobs` method to make it runnable. If I omit `process_jobs`, the example is impossible to run.

    One more thought: Maybe `add_job` should be async? No, "basic job queue" usually implies a simple data structure.

    I'll provide the two requested methods plus a `process_next_job` method to satisfy the "FIFO" and "processed" requirements.

    Wait, if I want to be strictly compliant with "Create a class with the following methods", I should probably only have those two. But then the example is impossible. I'll include `process_next_job`.

    Let's double check the requirement: "Jobs should be processed in FIFO order".
    This confirms that there *is* a processing step.
</reasoning_content>

<content>
```python
from collections import deque
from typing import Dict, Optional

class JobQueue:
    def __init__(self):
        # Stores jobs as (job_id, data) in FIFO order
        self.queue: deque = deque()
        # Stores results of completed jobs
        self.results: Dict[str, dict] = {}

    def add_job(self, job_id: str, data: dict) -> str:
        """Add a job to the queue and return the job_id."""
        self.queue.append((job_id, data))
        return job_id

    def get_result(self, job_id: str) -> dict | None:
        """Get the result of a completed job by its ID."""
        return self.results.get(job_id)

    def process_next_job(self) -> bool:
        """
        Internal helper to simulate processing. 
        Moves a job from the queue to the results dictionary.
        """
        if self.queue:
            job_id, data = self.queue.popleft()
            # Simulate processing logic
            self.results[job_id] = {"status": "completed", "data": data}
            return True
        return False
```
</content>