You are working on a project that involves storing data in a cloud-based database using the Firestore service. You have a function `_store_results` that takes three parameters: `bucket` (the name of the storage bucket where the files are stored), `file_name` (the name of the file), and `objects` (a list of objects containing information).

The function is responsible for storing each object's information in the Firestore database. Each object has a `name` attribute, which should be used as the document ID in the Firestore collection.

To store the information for each object, the function needs to perform the following steps:
1. Connect to the Firestore database using the `firestore.Client()` method.
2. Iterate over each object in the `objects` list.
3. Create a document in the Firestore collection `tags` with the document ID set to the lowercase version of the object's `name` attribute.
4. Set the document data as follows:
   - Key: `photo_urls`
   - Value: An array containing a single URL string in the format `https://storage.googleapis.com/{bucket}/{file_name}`. The `{bucket}` and `{file_name}` placeholders should be replaced with the corresponding values from the function parameters.
5. Perform a merge operation on the document to update it if it already exists.

Your task is to complete the implementation of the `_store_results` function according to the given requirements.

Write the code for the `_store_results` function.
user
Sure, here's how you can implement the `_store_results` function:

```python
import os
import json
import firebase_admin
from firebase_admin import firestore

# Initialize Firebase Admin with your service account credentials
cwd = os.getcwd()
os.chdir(os.path.join(cwd, 'path_to_your_firebase_admin_module'))
firbase_admin.initialize_app()

def _store_results(bucket, file_name, objects):
    client = firestore.Client()

    # Create the tags collection if it doesn't exist
    tags_ref = client.collection('tags')

    for obj in objects:
        doc_ref = tags_ref.document(obj['name'].lower())

        # Set the photo_urls field
        photo_urls = [
            f'https://storage.googleapis.com/{bucket}/{file_name}'
        ]

        doc_snapshot = doc_ref.get()

        # If the document does not exist, create it
        if not doc_snapshot.exists():
            doc_ref.set({'photo_urls': photo_urls})
        else:
            # Merge the photo_urls array with the existing one
            doc_ref.update({'photo_urls': firestore.FieldArray.compareAndSet(doc_snapshot['photo_urls'] + photo_urls)})

        # This is optional. You can perform additional updates, like updating the object's name field
        # obj_ref = tags_ref.document(obj['name'].lower())
        # obj_ref.update({'name': obj['name']})
```

Note that this code assumes that the `bucket` and `file_name` parameters are strings and the `objects` parameter is a list of dictionaries where each dictionary represents an object. The `name` attribute of each object should be a string. If this is not your case, you'll need to adapt the code accordingly. Also, make sure that you've installed the Firebase SDK for Python (`firebase-admin`).
assistant
You are working on a project that involves storing data in a cloud-based database using the Firestore service. You have a function `_store_results` that takes three parameters: `bucket` (the name of the storage bucket where the files are stored), `file_name` (the name of the file), and `objects` (a list of objects containing information).

The function is responsible for storing each object's information in the Firestore database. Each object has a `name` attribute, which should be used as the document ID in the Firestore collection.

To store the information for each object, the function needs to perform the following steps:
1. Connect to the Firestore database using the `firestore.Client()` method.
2. Iterate over each object in the `objects` list.
3. Create a document in the Firestore collection `tags` with the document ID set to the lowercase version of the object's `name` attribute.
4. Set the document data as follows:
   - Key: `photo_urls`
   - Value: An array containing a single URL string in the format `https://storage.googleapis.com/{bucket}/{file_name}`. The `{bucket}` and `{file_name}` placeholders should be replaced with the corresponding values from the function parameters.
5. Perform a merge operation on the document to update it if it already exists.

Your task is to complete the implementation of the `_store_results` function according to the given requirements.

Write the code for the `_store_results` function.
user
Sure, I can help you with that. Here's a Python function that should meet your requirements. Please note that you need to have the `google-cloud-firestore` library installed to use the `firestore.Client()` method.

```python
from google.cloud import firestore

def _store_results(bucket, file_name, objects):
    # Step 1: Connect to the Firestore database
    db = firestore.Client()

    # Step 2: Iterate over each object in the objects list
    for obj in objects:
        # Step 3: Create a document in the Firestore collection 'tags'
        # The document ID is set to the lowercase version of the object's 'name' attribute
        doc_ref = db.collection(u'tags').document(obj.name.lower())

        # Step 4: Set the document data
        # Key: 'photo_urls'
        # Value: An array containing a single URL string in the format 'https://storage.googleapis.com/{bucket}/{file_name}'
        data = {
            u'photo_urls': [f'https://storage.googleapis.com/{bucket}/{file_name}']
        }

        # Step 5: Perform a merge operation on the document to update it if it already exists
        doc_ref.set(data, merge=True)
```

This function connects to the Firestore database, iterates over each object in the `objects` list, creates a document in the `tags` collection with the document ID set to the lowercase version of the object's `name` attribute, sets the document data with the specified key and value, and performs a merge operation on the document to update it if it already exists.
assistant