'Get total space available on the mountpoints:
1. Main memory
2. Memory Card A
3. Memory Card B
@return: A 3 element list with total space in bytes of (1, 2, 3). If a
particular device doesn\'t have any of these locations it should return 0.'

def total_space(self, end_session=True):

    if self.verbose:
        logger().info(('%s.total_space()' % self.__class__.__name__))
    capacity = 0
    if isosx:
        if ('iPod' in self.sources):
            connected_device = self.sources['iPod']
            capacity = self.iTunes.sources[connected_device].capacity()
    return (capacity, (-1), (-1))
