In Python:

Create a new class, SMS_store. The class will instantiate SMS_store objects, similar to an inbox or outbox on a cellphone: my_inbox = SMS_store() This store can hold multiple SMS messages (i.e. its internal state will just be a list of messages). Each message will be represented as a tuple:

(has_been_viewed, from_number, time_arrived, text_of_SMS)

The inbox object should provide these methods:

my_inbox.add_new_arrival(from_number, time_arrived, text_of_SMS)

# Makes new SMS tuple, inserts it after other messages

# in the store. When creating this message, its

# has_been_viewed status is set False.

my_inbox.message_count()

# Returns the number of sms messages in my_inbox

my_inbox.get_unread_indexes()

# Returns list of indexes of all not-yet-viewed SMS messages

my_inbox.get_message(i)

# Return (from_number, time_arrived, text_of_sms) for message[i]

# Also change its state to "has been viewed". # If there is no message at position i, return None

my_inbox.delete(i)

# Delete the message at index i my_inbox.clear()

# Delete all messages from inbox Write the class, create a message store object, write tests for these methods, and implement the methods.