<reasoning_content>
*   Task: Implement a basic job queue in Python.
    *    Class Name: `JobQueue`.
    *    Methods:
        *   `add_job(job_id: str, data: dict) -> str` (adds job, returns ID).
        *   `get_result(job_id: str) -> dict | None` (gets result).
    *    Order: FIFO.
    *    Storage: Internal storage for jobs until processed.
    *    Identification: Unique `job_id`.
    *    Constraints: Write *only* the Python code, no explanations.

    *   Since it's a basic job queue, I need a way to store pending jobs and completed results.
    *   `collections.deque` is good for FIFO (adding to right, popping from left).
    *   A dictionary `results` to store results once they are "processed".
    *   *Correction on "Processing"*: The prompt doesn't explicitly ask for a background worker thread, but usually, a "JobQueue" implies a way to process. However, the requirement "Jobs should be processed in FIFO" suggests a processing mechanism or at least a way to trigger it. Since the user wants `get_result`, I need to define how a job transitions from "pending" to "completed".
    *   Wait, the prompt says "The queue should store jobs internally until they are processed".
    *   Let's look at the example: `queue.add_job(...)` then `queue.get_result(...)`.
    *   In a real system, there's a worker. In this basic implementation, I should probably include a `process_jobs()` method or simulate it, but the prompt only asks for `add_job` and `get_result`.
    *   If I only have those two methods, how does a job get "completed"?
    *   Maybe I should implement a simple `process_all()` method or similar, or just have a `complete_job` method?
    *   Let's re-read: "Jobs should be processed in FIFO".
    *   Usually, in these coding tests, if a worker isn't specified, I should provide a method to process them or simulate a processing step.
    *   Actually, looking at the signature: `add_job` returns the ID. `get_result` gets the result.
    *   To make `get_result` return something non-None, a job must be "processed". I'll add a `process_jobs` method to fulfill the FIFO requirement, or just have the `add_job` method put it in a list and provide a way to trigger processing.
    *   Wait, the prompt doesn't ask for a `process_jobs` method in the *requirements* list, but it says "Jobs should be processed in FIFO".
    *   If I only provide `add_job` and `get_result`, `get_result` will always be `None` unless I have a way to change state.
    *   I will include a `process_jobs` method to allow the queue to actually function, even though it's not strictly in the requirement list, or I can make `add_job` trigger a mock processing.
    *   Actually, let's look at the requirement: "Jobs should be processed in FIFO". This implies a processing step. I'll add a `process_next_job` method.

    *Refined Plan:*
    1.  `self.queue`: A `collections.deque` to store `(job_id, data)`.
    2.  `self.results`: A dictionary to store `job_id -> result`.
    3.  `add_job(job_id, data)`: Appends to `queue`, returns `job_id`.
    4.  `process_jobs()`: Pops from `queue`, simulates work, puts in `results`. (I'll add this to make the code functional).
    5.  `get_result(job_id)`: Looks up in `results`.

    *Alternative interpretation:*
    Maybe the user wants the `JobQueue` to handle the "processing" automatically? But without a thread or a loop, it won't happen.
    Let's stick to the requested methods and add a `process_jobs` method to satisfy the "processed in FIFO" requirement.

    Actually, many such prompts expect a simple storage and a method to "complete" a job. But since the requirement is "processed in FIFO", I'll implement a `process_jobs` method that processes all currently pending jobs in order.

    *Wait*, I should check if I should just mock the processing inside `add_job`? No, that's not a queue.
    Let's provide the requested methods exactly and a helper to process.

    *Actually*, looking at the example:
    `job_id = queue.add_job(...)`
    `# After processing...`
    `result = queue.get_result("job1")`
    The "# After processing..." comment implies that something happens *outside* the `add_job` call. This suggests there should be a method to trigger processing or the process is external. But since it's a "JobQueue" class, I'll provide a `process_jobs` method.

    *Revised Plan (Minimalist to strictly follow prompt):*
    Required methods: `add_job`, `get_result`.
    To fulfill "processed in FIFO", I will add a `process_jobs` method.

    ```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 process_jobs(self):
            while self.queue:
                job_id, data = self.queue.popleft()
                # Simulate processing logic here
                self.results[job_id] = {"status": "completed", "data": data}

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

    Wait, the instructions say "Write only the Python code".

    Let's refine the `process_jobs` logic. If I don't include `process_jobs`, `get_result` will always be `None`. If I do include it, I'm adding a method not explicitly asked for but necessary for the logic.

    Actually, maybe the user wants me to simulate the processing? No, the comment `# After processing...` usually implies the user will call a method or a thread will run. I'll provide `process_jobs`.

    Wait, I'll check if there's any other way. What if `add_job` is supposed to be asynchronous? Python's `threading` or `asyncio`. That might be overkill for a "basic" queue.

    Let's stick to a simple FIFO queue with a processing method.

    Actually, I'll rename `process_jobs` to something like `process_next_job` or just `process_all`. To be safe and clean, I'll just provide the requested methods and a simple `process_jobs`.

    Let's double check the prompt: "Jobs should be processed in FIFO". This is a behavioral requirement. If I don't provide a way to process, the requirement isn't met.

    ```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 process_jobs(self):
            while self._queue:
                job_id, data = self._queue.popleft()
                # Simulate processing
                self._results[job_id] = {"status": "success", "result": data}

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

    Actually, some interview questions want the "processing" to be a method like `execute_next()`. I'll stick to a method that processes all pending jobs to satisfy "FIFO".

    One last thought: The prompt says "Write only the Python code".

    Wait, looking at the example again:
    `job_id = queue.add_job("job1", {"task": "process_data"})`
    `# After processing...`
    `result = queue.get_result("job1")`
    This implies that the processing happens *between* these two lines. If I provide `process_jobs`, the user would call `queue.process_jobs()` in that comment area.

    Let's write the final version.

    ```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 process_jobs(self) -> None:
            while self.queue:
                job_id, data = self.queue.popleft()
                # Simulate actual processing of the data
                self.results[job_id] = {"result": data, "status": "completed"}

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

    Actually, should I use a Thread? "Implement a basic job queue". Usually, a "queue" in Python context might imply `queue.Queue` which is thread-safe. But the prompt asks for a class `JobQueue` with specific methods.

    I'll stick to the simple deque approach.

    One minor detail: `dict | None` is Python 3.10+ syntax. I should make sure it's compatible or just use `Optional`. But the prompt uses `dict | None`, so I'll use that.

    Wait, I'll make sure to include the imports.

    Final check:
    1. `JobQueue` class? Yes.
    2. `add_job(job_id, data)`? Yes.
    3. `get_result(job_id)`? Yes.
    4. FIFO? Yes (deque popleft).
    5. Internal storage? Yes.
    6. Unique job_id? Returned by `add_job`.

    Wait, if the user doesn't call `process_jobs`, `get_result` is always None. I will include `process_jobs` as it's necessary for the requirement "Jobs should be processed...".

    Actually, maybe I should just make `add_job` trigger a mock process? No, that's not FIFO order for the whole queue.

    I'll include `process_jobs`.
</reasoning_content>

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

class JobQueue:
    def __init__(self):
        self._queue: deque[tuple[str, dict]] = deque()
        self._results: Dict[str, dict] = {}

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

    def process_jobs(self) -> None:
        """
        Processes all jobs currently in the queue in FIFO order.
        """
        while self._queue:
            job_id, data = self._queue.popleft()
            # Simulate processing logic
            self._results[job_id] = {"status": "completed", "data": data}

    def get_result(self, job_id: str) -> dict | None:
        """
        Returns the result of a completed job or None if not completed.
        """
        return self._results.get(job_id)
```
</content>