1. General python) Write the constructor for the class C(x,y,z) that receives three parameters with default vilues 10 , 20 , and 30 , and creates an object with attributes x,y, and z, as shown in the expected results. 2. (Arrays) Write the function cross.array(A) that receives a 2D array A and sets to zero all elements in the middle row and middle column of A. You may assume that the number of rows and columns in A is odd. 3. (Lists) Write the function words_of_length k(W,k,n) that receives a list of words W and integers k and n and returns a list containing the first n words in W that have length k (or all the words in W that have length k in there are fewer than n such words). 4. (Sets) A reverse pair is a pair of words ( w0,w1 ) where w0 is the reverse of w1 and w0