Here we will practice writing a simple function. Write a

function that takes as input a column vector, and generates as output a column vector that is the

concatenation of the vector to itself. For example, if input is $[5,4,3],$ then output is $[5,4,$

$3,5,4,3].$ If the input is not of size N x$1,$ display a message saying $$This function works only

for column vectors.