What does this expression do?(Python) : I have this line:

    theta1 = zeros((3,2)) #this is a 3x2 matrix
    theta0 = zeros((2,1)) #this is a 2x1 matrix
    thetares = theta1.dot(theta0) #3x2 * 2x1 -> 3x1

    res0 = thetares.T.dot(thetares)[0,0] #result 0.0
    res1 = thetares.T.dot(thetares)      #result [[0.]]

but I dont know, what does this **[0,0]** at the end of the expression of **res0**. res0 and res1 result will be a 1x1 matrix