findpeaks fails to execure in Cody coursework

The problem concerns the course:

Introduction to Digital Signal Processing, by Richard Radke; Lesson 2: Spectrum Representation of Signals

In particular in Lesson 2.1 and 2.2 the reference solution fails against the Test Suite with the following error:

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Undefined function 'findpeaks' for input arguments of type 'double'.

Error in Test1 (line 3)

[pks,locs] = findpeaks(y);

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Also in student environment a copied correct solution fails the test.

In Matlab-online or in an computer-installed Matlab (2017b) the test (copied from coursework) works.

There is a way to use these lesson without changing the Test Suite deleting the call to findpeaks ??

best regards

Simone Orcioni

P.S.

In the same Test Suite also the function

ymat = chirp(t,0,t0,f0);

gives the error:

Undefined function 'chirp' for input arguments of type 'double'.

Error in Hidden test1