CPQ Price Engine - how to pass Customer ID when using 'CalculatePrice' API

Summary:

Hello - we're using Oracle CPQ's price engine to dynamically calculate price based on a variety of inputs (customer ID, item, item categorization, etc.). For our use-case, there are 3rd party appliations that need to use Oracle CPQ's calculatePrice API to obtain the same dynamically calculated price.

For some additional background, we're mapping the following primary Price Engine attributes to Commerce:
Price Engine > Commerce

• Customer ID (customerID_c) > Customer ID (_customer_id) *seeded customer ID that's provided in Oracle CPQ's standard process
• Customer Class (customerClass_c) > Customer Class (customerClass_c)
• Quantity (quantity) > Quantity (_price_quantity)
• Item Class (ItemClass_c) > Item Class (part_custom_field_1)