Help in Matlab Co-simulation

I need some help here. I understand that topics regarding on Matlab integration have been discussed in here and i tried to read tutorials but i still face alot of errors. example like this code below which i want to see how it works, the optisystem keeps giving me this error “Encountered an improper Argument”

Code:
Attenuation_dB = 0; % Example: 3 dB
Attenuation_Factor = 10^(-Attenuation_dB / 20); % Field attenuation factor

OutputPort1 = InputPort1;

if isfield(InputPort1, ‘Sampled’) && isfield(InputPort1.Sampled, ‘Signal’) && isnumeric(InputPort1.Sampled.Signal)
OutputPort1.Sampled.Signal = InputPort1.Sampled.Signal .* Attenuation_Factor;
else
disp(‘Warning: Invalid optical signal structure.’);
end