def orphan_strategy= orphan_strategy
      # Check value of orphan strategy, only rootify, adopt, restrict or destroy is allowed
      if [:rootify, :adopt, :restrict, :destroy].include? orphan_strategy
        class_variable_set :@@orphan_strategy, orphan_strategy
      else
        raise Ancestry::AncestryException.new("Invalid orphan strategy, valid ones are :rootify,:adopt, :restrict and :destroy.")
      end
    end
def orphan_strategy= orphan_strategy
      # Check value of orphan strategy, only rootify, adopt, restrict or destroy is allowed
      if [:rootify, :adopt, :restrict, :destroy].include? orphan_strategy
        class_variable_set :@@orphan_strategy, orphan_strategy
      else
        raise Ancestry::AncestryException.new("Invalid orphan strategy, valid ones are :rootify,:adopt, :restrict and :destroy.")
      end
    end
Orphan strategy writer