Pranav

    from copy import deepcopy # create a copy of a list.
    # Your code snippet
    for vpc in vpcs:
        acc_data = {
            "account_number": vpc["ResourceOwnerId"],
            "vpc": [vpc['ResourceId']]
        }
        acc_list.append(acc_data)

    # Add this
    new_acc_list = deepcopy(acc_list)
    previous_acc_numbers = {} # int: index

    for acc_data in acc_list:
        acc_number, acc_vpc = acc_data.get(account_number), acc_data.get("vpc")
        if acc_number in previous_acc_numbers:
            new_acc_list[previous_acc_numbers.get(acc_number)].get("vpc").append(acc_data.get("vpc"))
    
    print(acc_list)