$```$

In $[]$: def knnclassifier$($xTr$,$yTr$,$xTe,k$)$:

function preds$=$knnclassifier$($xTr$,$yTr$,$xTe,k$)$;

k$-$nn classifier

Input:

xTr $=$ nxd input matrix with n row$-$vectors of dimensionality d

yTr $=$ n$-$dimensional vector of labels

xTe $=$ mxd input matrix with m row$-$vectors of dimensionality d

k $=$ number of nearest neighbors to be found

Output:

preds $=$ predicted labels, ie preds$($i$)$ is the predicted label of xTe$($i$,$:$)$

$"""$

# fix array shapes

yTr $=$ yTr$.$flatten$()$

# YOUR CODE HERE

raise NotImplementedError$()$

$```$