MATLAB!! Why do I get this error? How do I fix it?

function z = conv(x, y) lx = length(x.data); ly = length(y. data): lz = 1x + ly - 1: z. offset = x. offset + y. offset; z. data = [] : if (lx > ly) yhat = sequence ([zeros(1, (lx - 1)) y.data(1:end) zeros (1, (lx -1))], z. offset): for n - 1:12 holder = (yhat (n: (n + lx 1))) : z. data (end + 1) = dot (x. data, holder): end z = sequence (z. data, z. offset): else xhat = sequence ([zeros (1, (lx - 1)) y.data(1:end) zeros(1, (ly -1))], z. offset): for n = 1:12 holder (xhat (n: (n + ly - 1))): z. data (end + 1) dota (y. data, holder): end z = sequence (z. data, z. offset): end z = sequence (z. data, z. offset): end Index exceeds the number of array elements (1). Error in sequence/cony (line 139) holder = (xhat (n: (n + ly - 1))); Error in test_lab2 Error in lab2 (line 14) test_1ab2(x, h): function z = conv(x, y) lx = length(x.data); ly = length(y. data): lz = 1x + ly - 1: z. offset = x. offset + y. offset; z. data = [] : if (lx > ly) yhat = sequence ([zeros(1, (lx - 1)) y.data(1:end) zeros (1, (lx -1))], z. offset): for n - 1:12 holder = (yhat (n: (n + lx 1))) : z. data (end + 1) = dot (x. data, holder): end z = sequence (z. data, z. offset): else xhat = sequence ([zeros (1, (lx - 1)) y.data(1:end) zeros(1, (ly -1))], z. offset): for n = 1:12 holder (xhat (n: (n + ly - 1))): z. data (end + 1) dota (y. data, holder): end z = sequence (z. data, z. offset): end z = sequence (z. data, z. offset): end Index exceeds the number of array elements (1). Error in sequence/cony (line 139) holder = (xhat (n: (n + ly - 1))); Error in test_lab2 Error in lab2 (line 14) test_1ab2(x, h)