solution.py

# Only-readable-once list
# Attention Agent.
# The White House is currently developing a mobile app that it can use to issue instructions to its undercover agents.

# Part of the functionality of this app is to have messages that can be read only once, and are then destroyed.
# As our best undercover developer, we need you to implement a SecureList class that will deliver this functionality.
# Behaviour different to the traditional list is outlined below:

# Accessing an item at any index should delete the item at that index eg:
# messages=SecureList([1,2,3,4])
# print messages[1]  # prints 2
# print messages     # prints [1,3,4]

# Printing the whole list should clear the whole list eg:
# messages=SecureList([1,2,3,4])
# print messages     # prints [1,2,3,4]
# print messages     # prints []

# Viewing the representation of the list should also clear the list eg:
# messages=SecureList([1,2,3,4])
# print "my messages are: %r."%messages     # prints "my messages are: [1,2,3,4].
# print messages     # prints []

# To complete this kata you need to be able to define a class that implements __getitem__(), __str__(), __repr__(),
# and possibly __len__().


class SecureList(list):
    def __str__(self):
        s = super().__str__()
        self.clear()
        return s

    def __repr__(self):
        s = super().__repr__()
        self.clear()
        return s

    def __getitem__(self, index):
        val = super().__getitem__(index)
        del self[index]
        return val