Help, problem with dsp.BiquadFilter

using the same code in this page https://www.mathworks.com/help/audio/examples/active-noise-control-using-a-filtered-x-lms-fir-adaptive-filter.html#zmw57dd0e848, during the execution I have a problem in this line

 sedondaryPathCoeffsActual = bandpass([zeros(delayS,1); ...
                       log(0.99*rand(N-delayS,1)+0.01).* ...
                       sign(randn(N-delayS,1)).*exp(-0.01*(1:N-delayS)')]);

I am not able to solve it, please help me.

[Walter Roberson]

What error message are you observing?

[Muhammad Younus]

Array formation and parentheses-style indexing with objects of class 'dsp.BiquadFilter' is not allowed. Use objects of class 'dsp.BiquadFilter' only as scalars or use a cell array.

Error in SecondaryPathCalculation (line 15) secondaryPathCoeffsActual = bandpass([zeros(delayS,1); ...