# File lib/amalgalite/database.rb, line 902
    def define_progress_handler( op_code_count = 25, callable = nil, &block )
      handler  = ( callable || block ).to_proc
      a = handler.arity
      raise ProgressHandlerError, "A progress handler expects 0 arguments, not #{a}" if a != 0
      @api.progress_handler( op_code_count, handler )
    end