docs: def add_content(self, **content):
          """
          Adds given content to the cache.
  
          Usage::
  
              >>> cache = Cache()
              >>> cache.add_content(John="Doe", Luke="Skywalker")
              True
              >>> cache
              {'Luke': 'Skywalker', 'John': 'Doe'}
  
          :param \*\*content: Content to add.
          :type \*\*content: \*\*
          :return: Method success.
          :rtype: bool
          """
  
          LOGGER.debug("> Adding '{0}' content to the cache.".format(self.__class__.__name__, content))
  
          self.update(**content)
          return True