from dataclasses import dataclass
 
@dataclass
class Book_list:
	name: str
	perunit_cost: float
	quantity_available: int = 0
		
	# function to calculate total cost	
	def total_cost(self) -> float:
		return self.perunit_cost * self.quantity_available
	
book = Book_list("Introduction to programming.", 300, 3)
x = book.total_cost()
 
# print the total cost
# of the book
print(x)
 
# print book details
print(book)
 
# 900
Book_list(name='Python programming.',
		perunit_cost=200,
		quantity_available=3)