def to_radians(*args)
      args = args.first if args.first.is_a?(Array)
      if args.size == 1
        args.first * (Math::PI / 180)
      else
        args.map{ |i| to_radians(i) }
      end
    end
def to_radians(*args)
      args = args.first if args.first.is_a?(Array)
      if args.size == 1
        args.first * (Math::PI / 180)
      else
        args.map{ |i| to_radians(i) }
      end
    end
Convert degrees to radians.
 If an array (or multiple arguments) is passed,
 converts each value and returns array.