I am getting the following error

When I inserted a MATLAB block in SIMULINK model to remove the spikes from the input.

CODER.NULLCOPY does not support inputs of class 'mxArray'.
Function 'Estimation of stator flux linkage vector /MATLAB Function' (#57.81.111), line 5, column 7:
"coder.nullcopy(zeros(size(u)))"
Launch diagnostic report.

The program I ran as follows:

function y = fcn(u)
%#codegen
coder.extrinsic('medfilt1');
u=medfilt1(u);
y = coder.nullcopy(zeros(size(u)));
y = u;

Any suggestions in this mater will be helpful.