defining a lot of exceptions in a module

exceptions.rb

    module Prawn  
      module Errors  
        
        exceptions = %w[ FailedObjectConversion InvalidPageLayout NotOnPage  
                        UnknownFont IncompatibleStringEncoding UnknownOption ]  
      
        exceptions.each { |e| const_set(e, Class.new(StandardError)) }  
      
      end  
    end