Senkou B (Leading Span B)

    Formula:
    (H + L) / 2  :: default period=52 :: shifted forward 26 bars

def senkou_b(data, period=52):
    """
    Senkou B (Leading Span B)

    Formula:
    (H + L) / 2  :: default period=52 :: shifted forward 26 bars
    """
    sb = conversion_base_line_helper(data, period)
    shift_by = np.repeat(np.nan, 26)
    sb = np.append(shift_by, sb)
    return sb