def now
      current_time = Time.now
      each_with_series do |series|
        return series if series.on_air?(current_time)
      end
      raise NotOnAirError, "Not on air precure!"
    end
def now
      current_time = Time.now
      each_with_series do |series|
        return series if series.on_air?(current_time)
      end
      raise NotOnAirError, "Not on air precure!"
    end
rubocop:disable Metrics/LineLength
 get current precure series
 @return [Rubicure::Series] current precure

 @raise [NotOnAirError] not onair!

 @example
   Precure.now
   #=> {:series_name=>"go_princess", :title=>"Go!プリンセスプリキュア", :started_date=>Sun, 01 Feb 2015, :girls=>["cure_flora", "cure_mermaid", "cure_twinkle", "cure_scarlet"]}