def in_use?(index)
      results = []
      index.each do |entry|
        box_data = entry.extra_data["box"]
        next if !box_data

        # If all the data matches, record it
        if box_data["name"] == self.name &&
          box_data["provider"] == self.provider.to_s &&
          box_data["version"] == self.version.to_s
          results << entry
        end
      end

      return nil if results.empty?
      results
    end
def in_use?(index)
      results = []
      index.each do |entry|
        box_data = entry.extra_data["box"]
        next if !box_data

        # If all the data matches, record it
        if box_data["name"] == self.name &&
          box_data["provider"] == self.provider.to_s &&
          box_data["version"] == self.version.to_s
          results << entry
        end
      end

      return nil if results.empty?
      results
    end
Checks if this box is in use according to the given machine
 index and returns the entries that appear to be using the box.

 The entries returned, if any, are not tested for validity
 with {MachineIndex::Entry#valid?}, so the caller should do that
 if the caller cares.

 @param [MachineIndex] index
 @return [Array<MachineIndex::Entry>]