unless Object.new.respond_to? :blank?
  class Object
    def blank?
      false
    end
  end

  class NilClass
    def blank?
      true
    end
  end

  class Set
    alias :blank? :empty?
  end

  class String
    def blank?
      not self =~ /[^\s]/
    end
  end

  class Array
    alias :blank? :empty?
  end

  class Hash
    alias :blank? :empty?
  end
end

unless Object.new.respond_to? :present?
  class Object
    def present?
      not blank?
    end
  end
end