```ruby
module Spree
  module Api
    module V1
      class InventoryUnitsController < Spree::Api::V1::BaseController
        before_filter :prepare_event, :only => :update

        def show
          @inventory_unit = inventory_unit
        end

        def update
          authorize! :update, Order

          inventory_unit.transaction do
            if inventory_unit.update_attributes(params[:inventory_unit])
              fire
              render :show, :status => 200
            else
              invalid_resource!(inventory_unit)
            end
          end
        end

        private

        def inventory_unit
          @inventory_unit ||= InventoryUnit.find(params[:id])
        end

        def prepare_event
          return unless @event = params[:fire]

          can_event = "can_#{@event}?"

          unless inventory_unit.respond_to?(can_event) &&
                 inventory_unit.send(can_event)
            render :text => { exception: "cannot transition to #{@event}" }.to_json,
                    :status => 200
            false
          end
        end

        def fire
          inventory_unit.send("#{@event}!") if @event
        end

      end
    end
  end
end
```

Convert 1.9 hash syntax to hashrocket syntax within inventory_units controller
user
```ruby
module Spree
  module Api
    module V1
      class InventoryUnitsController < Spree::Api::V1::BaseController
        before_filter :prepare_event, :only => :update

        def show
          @inventory_unit = inventory_unit
        end

        def update
          authorize! :update, Order

          inventory_unit.transaction do
            if inventory_unit.update_attributes(params[:inventory_unit])
              fire
              render :show, :status => 200
            else
              invalid_resource!(inventory_unit)
            end
          end
        end

        private

        def inventory_unit
          @inventory_unit ||= InventoryUnit.find(params[:id])
        end

        def prepare_event
          return unless @event = params[:fire]

          can_event = "can_#{@event}?"

          unless inventory_unit.respond_to?(can_event) &&
                 inventory_unit.send(can_event)
            render :text => { :exception => "cannot transition to #{@event}" }.to_json,
                    :status => 200
            false
          end
        end

        def fire
          inventory_unit.send("#{@event}!") if @event
        end

      end
    end
  end
end
```
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