AsWitness(cc pb.ConfigChange) bool {  if cc.Type == pb.AddWitness {   _, ok := m.members.Addresses[cc.NodeID]   return ok  }  return false }  func (m *membership) isAddingWitnessAsObserver(cc pb.ConfigChange) bool {  if cc.Type == pb.AddObserver {   _, ok := m.members.Witnesses[cc.NodeID]   return ok  }  return false }  func (m *membership) isAddingWitnessAsNode(cc pb.ConfigChange) bool {  if cc.Type == pb.AddNode {   _, ok := m.members.Witnesses[cc.NodeID]   return ok  }  return false }  func (m *membership) isAdding