code: def senkou_b(data, period=52):
      
      sb = conversion_base_line_helper(data, period)
      shift_by = np.repeat(np.nan, 26)
      sb = np.append(shift_by, sb)
      return sb
docs: Senkou B (Leading Span B)
  
      Formula:
      (H + L) / 2  :: default period=52 :: shifted forward 26 bars