Code level doubt

E-Commerce
1

Hi everybody,

I am not sure, whether one can ask code level doubts here.
But I am stuck in a section.

in cart.py

I found the function for setting price list, but i didn’t understand the code

item.price_list_rate = item.discount_percentage = item.rate = item.amount = None

and

quotation.run_method("set_price_list_and_item_details")

in the below function

def set_price_list_and_rate(quotation, cart_settings):
	"""set price list based on billing territory"""

	_set_price_list(quotation, cart_settings)

	# reset values
	quotation.price_list_currency = quotation.currency = \
		quotation.plc_conversion_rate = quotation.conversion_rate = None
	for item in quotation.get("items"):				
		item.price_list_rate = item.discount_percentage = item.rate = item.amount = None

	# refetch values
	quotation.run_method("set_price_list_and_item_details")

	if hasattr(frappe.local, "cookie_manager"):
		# set it in cookies for using in product page
		frappe.local.cookie_manager.set_cookie("selling_price_list", quotation.selling_price_list)

Please let me know the how the price_list_rate is assigned here?