def unit_step(unit, *alternates)
      is_frequency = @every == unit
      if ([unit] + alternates).any? { |u| @options.key?(u) } && !is_frequency
        # smallest unit, increment by 1
        { step_key(unit) => 1 }
      elsif is_frequency
        { step_key(unit) => @interval }
      end
    end
def unit_step(unit, *alternates)
      is_frequency = @every == unit
      if ([unit] + alternates).any? { |u| @options.key?(u) } && !is_frequency
        # smallest unit, increment by 1
        { step_key(unit) => 1 }
      elsif is_frequency
        { step_key(unit) => @interval }
      end
    end
@private

 Returns hash representing unit and amount to advance time
 when options contain given unit as a key or as a value of
 the key :every in options

 options = { every: :day, hour: 8.12 }
 unit_step(:minute)
 => nil
 unit_step(:hour)
 => { hour: 1 }

 options = { every: :hour, interval: 6 }
 unit_step(:minute)
 => nil
 unit_step(:hour)
 => { hour: 6 }