'Compute the space  left in item inventory.
:return: The space left in item inventory. 0 if the player has more item than his item inventory can carry.
:rtype: int'

@classmethod
def get_space_left(cls):

    _inventory.retrieve_inventories_size()
    space_left = (_inventory.item_inventory_size - cls.get_space_used())
    return (space_left if (space_left >= 0) else 0)
