Gets given content from the cache.

        Usage::

            >>> cache = Cache()
            >>> cache.add_content(John="Doe", Luke="Skywalker")
            True
            >>> cache.get_content("Luke")
            'Skywalker'

        :param key: Content to retrieve.
        :type key: object
        :return: Content.
        :rtype: object

def get_content(self, key):
        """
        Gets given content from the cache.

        Usage::

            >>> cache = Cache()
            >>> cache.add_content(John="Doe", Luke="Skywalker")
            True
            >>> cache.get_content("Luke")
            'Skywalker'

        :param key: Content to retrieve.
        :type key: object
        :return: Content.
        :rtype: object
        """

        LOGGER.debug("> Retrieving '{0}' content from the cache.".format(self.__class__.__name__, key))

        return self.get(key)