#%% Class def

class  Inventory:
    
    # Class constructor:
    def __init__(self, n_init):
        # Definition of attribute of name n:
        self.n = n_init
        
    # Def of method of name accum:
    def accum(self, dn):
        self.n += dn     
        
    # Def of method of name value:
    def calc_value(self, v):
        val_invent = self.n * v
        return val_invent


#%% Instantiation of class Inventory

inventory_1 = Inventory(10)  # Instance or object called inventory_1

#%% Program part where the inventory_1 object is used

# Calling the method named accum:
inventory_1.accum(2)

# Reading the attribute named n:
contents_inventory = inventory_1.n
print(f'Contents of inventory: {contents_inventory}')

# Calling the method named value:
value_element = 100  # Value per element in inventory
value_inventory = inventory_1.calc_value(value_element)
print(f'Value of inventory: {value_inventory}')