This is the next big thing. We promise!

For our social network, we are going to need a Panda class which behaves like that:

ivo = Panda("Ivo", "[email protected]", "male")

ivo.name() == "Ivo" # True
ivo.email() == "[email protected]"  # True
ivo.gender() == "male" # True
ivo.isMale() == True # True
ivo.isFemale() == False # True

The Panda class also should be possible to:

• Be turned into a string
• Be hashed and used as a key in a dictionary (__eq__ and __hash__)
• Make sure that the email is a valid email!

Two Panda instances are equal if they have matching name, email and gender attributes.

Now it is time for our social network!

Implement a class, called PandaSocialNetwork, which has the following public methods:

• add_panda(panda) - this method adds a panda to the social network. The panda has 0 friends for now. If the panda is already in the network, raise an PandaAlreadyThere error.
• has_panda(panda) - returns True or False if the panda is in the network or not.
• make_friends(panda1, panda2) - makes the two pandas friends. Raise PandasAlreadyFriends if they are already friends. The friendship is two-ways - panda1 is a friend with panda2 and panda2 is a friend with panda1. If panda1 or panda2 are not members of the network, add them!
• are_friends(panda1, panda2) - returns True if the pandas are friends. Otherwise, False
• friends_of(panda) - returns a list of Panda with the friends of the given panda. Returns False if the panda is not a member of the network.
• connection_level(panda1, panda2) - returns the connection level between panda1 and panda2. If they are friends, the level is 1. Otherwise, count the number of friends you need to go through from panda in order to get to panda2. If they are not connected at all, return -1! Return False if one of the pandas are not member of the network.
• are_connected(panda1, panda2) - return True if the pandas are connected somehow, between friends, or False otherwise.
• how_many_gender_in_network(level, panda, gender) - returns the number of gender pandas (male of female) that in the panda network in that many levels deep. If level == 2, we will have to look in all friends of panda and all of their friends too. And count

network = PandaSocialNetwork()
ivo = Panda("Ivo", "[email protected]", "male")
rado = Panda("Rado", "[email protected]", "male")
tony = Panda("Tony", "[email protected]", "female")

for panda in [ivo, rado, tony]:
    network.add(panda)

network.make_friends(ivo, rado)
network.make_friends(rado, tony)

network.connection_level(ivo, rado) == 1 # True
network.connection_level(ivo, tony) == 2 # True

network.how_many_gender_in_network(1, rado, "female") == 1 # True

The next thing our social network is going to do is saving to your hard drive.

Write a function that saves the hole social network to a file. The format ot that file is at your choice. You have to be able to load it next time. So all the data in the network must be written down to that file.

Write a function that loads the hole social network from a file. All the pandas and all the relations.