how to fix matlab Function Block Issue ??

i am using MATLAB FUNTion Block as a rely for my model such as

function y = fcn(P,T)

if(T <= 12.0)

y=1;

else

if (P <= 4800000)

y=0;

else

y=1;

end

end

and it is working very well

but i want to use Mean of 5 Maximum peaks value for a specific interval

so i am using following code in my matlab function block

function y = fcn(P,T)

if(T <= 12.0)

y=1;

else

if ((mean(maxk(findpeaks(P((T >= 12) & (T <= 12.1))),5))) <= 4800000)

y=0;

else

y=1;

end

end

but where ever i put this command {(mean(maxk(findpeaks(P((T >= 12) & (T <= 12.1))),5)))} in matlab function error appear where as this command is working properly in command window

this is the error i am facing and i am unable to understand how i can fix it

Function 'maxk' is not supported for code generation. Consider adding coder.extrinsic('maxk') at the top of the function to bypass code generation