blank?

class NilClass
  def blank?
    true
  end
  def not_blank?
    !blank?
  end
end
class String
  def blank?
    self.strip.empty?
  end
  def not_blank?
    !blank?
  end
end
class FalseClass
  def blank?
    true
  end
  def not_blank?
    !blank?
  end
end
class TrueClass
  def blank?
    false
  end
  def not_blank?
    !blank?
  end
end
class Object
  def blank?
    respond_to?(:empty?) ? empty? : !self
  end
  def not_blank?
    !blank?
  end
end