Please help me with this.

the question is :

• Define a pytest test class'TestingInventoryCreation'which tests the behavior of the'__init__'method with the following tests:
• Define a pytest test method'test_creating_empty_inventory', which creates an empty inventory and checks if its 'balance_inventory' is an empty dict.
• Define a pytest test method'test_creating_specified_inventory', which creates an inventory instance with input {'iPhone Model X':100, 'Xiaomi Model Y': 1000, 'Nokia Model Z':25}.
• Define a pytest test method'test_creating_inventory_with_list', which checks if the'__init__'method raises a TypeError with the message "Input inventory must be a dictionary" when a list "['iPhone Model X', 'Xiaomi Model Y', 'Nokia Model Z']" is passed as input.
• Define a pytest test method'test_creating_inventory_with_numeric_keys', which checks if the'__init__'method raises a ValueError with the message "Mobile model name must be a string", when the dict {1:'iPhone Model X', 2:'Xiaomi Model Y', 3:'Nokia Model Z'} is passed as input.
• Define a pytest test method'test_creating_inventory_with_nonnumeric_values', which checks if the'__init__'method raises a ValueError with the message "No. of mobiles must be a positive integer" when the dict {'iPhone Model X':'100', 'Xiaomi Model Y': '1000', 'Nokia Model Z':'25'} is passed as input.
• Define a pytest test method'test_creating_inventory_with_negative_value', which checks if the'__init__'method raises a ValueError with the message "No. of mobiles must be a positive integer" when the dict {'iPhone Model X':-45, 'Xiaomi Model Y': 200, 'Nokia Model Z':25} is passed as input.

I have solved the first step:

class MobileInventory:

balance_inventory = 'None'

def __init__(self,inventory={}):

if type(inventory) is not dict:

raise TypeError("Input inventory must be a dictionary")

for key in inventory:

if type(key) is not str:

raise ValueError("Mobile model name must be a string")

if type(inventory[key]) is int:

if inventory[key] < 0:

raise ValueError("No. of mobiles must be a positive integer")

else:

raise ValueError("No. of mobiles must be a positive integer")

self.balance_inventory = inventory

def add_stock(self, new_stock):

if type(new_stock) is not dict:

raise TypeError("Input inventory must be a dictionary")

for key in new_stock:

if type(key) is not str:

raise ValueError("Mobile model name must be a string")

if type(new_stock[key]) is int:

if new_stock[key] < 0:

raise ValueError("No. of mobiles must be a positive integer")

else:

raise ValueError("No. of mobiles must be a positive integer")

self.balance_inventory.update(new_stock)

def sell_stock(self,requested_stock):

if type(requested_stock) is not dict:

raise TypeError("Input inventory must be a dictionary")

for key in requested_stock:

if type(key) is not str:

raise ValueError("Mobile model name must be a string")

if type(requested_stock[key]) is int:

if requested_stock[key] < 0:

raise ValueError("No. of mobiles must be a positive integer")

else:

raise ValueError("No. of mobiles must be a positive integer")

try:

if self.balance_inventory[key] < requested_stock[key]:

raise ValueError("Insufficient Stock")

except:

raise ValueError("No Stock. New Model Request")

self.balance_inventory[key] =- requested_stock[key]