merge the array elements with another array which is part of mongo collection

I have the below collection with the name sample_collection.

{'_id': ObjectId('603e9cc2784fa0d80d8672cd'),
'name': 'balaji',
'**B**': [{'price': 1, 'price_range': 'G'},
 {'price': 6, 'price_range': 'F'},
 {'price': 4, 'price_range': 'C'}]}

and I have one array with name A = [{'price': 22, 'price_range': 'X'}, {'price': 33, 'price_range': 'U'} ]

I am trying to merge the elements of the array A to the array with name B which is part of the above collection with the below pymongo query.

db.sample_collection.update_one({"name": "balaji"}, {"$addToSet": {"B": A}})

However, I see that the array as a whole is getting merged with the above collection, as shown below.

[{'_id': ObjectId('603e9cc2784fa0d80d8672cd'),
'name': 'balaji',
'B': [{'price': 1, 'price_range': 'G'},
{'price': 6, 'price_range': 'F'},
{'price': 4, 'price_range': 'C'},
[{'price': 22, 'price_range': "X"}
{'price': 33, 'price_range': 'U'}]]} (we can see another square brackets for 22 and 33)

however I need the elements of the array A(but not the array itself) to be merged with the collection array B and the expected result needs to be

[{'_id': ObjectId('603e9cc2784fa0d80d8672cd'),
'name': 'balaji',
'B': [{'price': 1, 'price_range': 'G'},
{'price': 6, 'price_range': 'F'},
{'price': 4, 'price_range': 'C'},
{'price': 22, 'price_range': "X"}
{'price': 33, 'price_range': 'U'}} (here there are no square brackets for elements with price 22 and 33)

May I know the query for the above please.