# File lib/sass/script/operation.rb, line 73
    def _perform(environment)
      literal1 = @operand1.perform(environment)
      literal2 = @operand2.perform(environment)

      begin
        opts(literal1.send(@operator, literal2))
      rescue NoMethodError => e
        raise e unless e.name.to_s == @operator.to_s
        raise Sass::SyntaxError.new("Undefined operation: \"#{literal1} #{@operator} #{literal2}\".")
      end
    end