@staticmethod
def _get_chassis_load_by_prios(chassis_info):
    """Retrieve the amount of ports by priorities hosted in the chassis.

        @param   chassis_info: list of (port, prio) hosted by this chassis
        @type    chassis_info: []
        @return: A list of (prio, number_of_ports) tuples.
        """
    chassis_load = {}
    for lrp, prio in chassis_info:
        chassis_load[prio] = chassis_load.get(prio, 0) + 1
    return chassis_load.items()
