# File lib/backports/2.0.0/range/size.rb, line 3
    def size
      return nil unless self.begin.is_a?(Numeric) && self.end.is_a?(Numeric)
      size = self.end - self.begin
      return 0 if size <= 0
      return size if size == Float::INFINITY
      if exclude_end?
        size.ceil
      else
        size.floor + 1
      end
    end