def priority(identity)
      priority = 0
      @brokers.each do |b|
        break if b.identity == identity
        priority += 1
      end
      priority
    end
def priority(identity)
      priority = 0
      @brokers.each do |b|
        break if b.identity == identity
        priority += 1
      end
      priority
    end
Determine priority of broker
 If broker not found, assign next available priority

 === Parameters
 identity(String):: Broker identity

 === Return
 (Integer):: Priority position of broker