I'm trying to port a PineScript indicator to the TakeProfit trading platform, but I'm running into type errors. When trying to use Bollinger Bands, I get this error:

Error: [internal] cannot create variable of type <class 'tuple[indie.Series[float], indie.Series[float], indie.Series[float]]'>

My code tries to access the Bollinger Bands results like this:

bb_result = Bb.new(self.close, length, mult)
bb_lower = bb_result[0][0]  # Extract the float value from the lower band
bb_upper = bb_result[2][0]  # Extract the float value from the upper band

Here's my Indie version of the indicator:

#indie:lang_version = 4
from math import isnan
from indie import indicator, SeriesF, MutSeriesF, plot, param, color, plot_style, line_style, Plot
from indie.algorithms import Sma, Tr, Bb, Highest, Lowest, LinReg

def mean(s1: SeriesF, s2: SeriesF, s3: SeriesF) -> float:
    return s1[0] / 4 + s2[0] / 4 + s3[0] / 2

def nan_to_zero(val: float) -> float:
    return 0 if isnan(val) else val

@indicator('Squeeze Momentum')
@param.int('length', default=20, min=1, title='BB Length')
@param.float('mult', default=1.5, title='BB MultFactor')
@param.int('length_kc', default=20, min=1, title='KC Length')
@param.float('mult_kc', default=1.5, title='KC MultFactor')
@param.bool('use_true_range', default=True, title='Use TrueRange (KC)')
@plot(style=plot_style.HISTOGRAM, line_width=4)
@plot(line_style=line_style.SOLID, line_width=4)  # TODO: use markers
def Main(self, length, mult, length_kc, mult_kc, use_true_range):
    # Get Bollinger Bands components individually
    bb_result = Bb.new(self.close, length, mult)
    bb_lower = bb_result[0][0]  # Extract the float value from the lower band
    bb_upper = bb_result[2][0]  # Extract the float value from the upper band
    
    # Calculate KC bands
    ma = Sma.new(self.close, length_kc)[0]
    
    # Calculate range based on user preference
    range_val = None
    if use_true_range:
        range_val = Tr.new()
    else:
        range_val = MutSeriesF.new(self.high[0] - self.low[0])
        
    # Calculate the moving average of the range
    range_ma = Sma.new(range_val, length_kc)[0]
    
    # Calculate KC bands
    kc_upper = ma + range_ma * mult_kc
    kc_lower = ma - range_ma * mult_kc
    
    # Determine squeeze conditions
    sqz_on = (bb_lower > kc_lower) and (bb_upper < kc_upper)
    sqz_off = (bb_lower < kc_lower) and (bb_upper > kc_upper)
    no_sqz = (sqz_on == False) and (sqz_off == False)
    
    # Calculate momentum value
    highest_high = Highest.new(self.high, length_kc)
    lowest_low = Lowest.new(self.low, length_kc)
    close_sma = Sma.new(self.close, length_kc)
    
    momentum_val = self.close[0] - mean(highest_high, lowest_low, close_sma)
    val_series = MutSeriesF.new(momentum_val)
    val = LinReg.new(val_series, length_kc)
    
    # Determine colors based on momentum
    bcolor = color.BLACK  # Default initialization
    if val[0] > 0:
        if val[0] > nan_to_zero(val[1]):
            bcolor = color.LIME
        else:
            bcolor = color.GREEN
    else:
        if val[0] < nan_to_zero(val[1]):
            bcolor = color.RED
        else:
            bcolor = color.MAROON
    
    # Determine squeeze state color
    scolor = color.GRAY
    if no_sqz:
        scolor = color.OLIVE
    elif sqz_on:
        scolor = color.NAVY
    
    # Return the plot values and colors
    return Plot(val[0], color=bcolor), Plot(0, color=scolor)

What I've tried

I've tried to:

1. Access Bollinger Bands values directly

2. Use different methods of unpacking the Bb.new() results

3. Store the result in a variable and access via indexing

4. Use the [0] index to extract float values

But I'm still getting the same error.

Questions

1. How do I correctly access the upper and lower Bollinger Bands in Indie platform?

2. Is there a specific way to handle the return type of Bb.new()?

Environment

• Indie version: 4