Suppose that K$1$ and K$2$ are kernels with feature maps $1$ and $2$ respectively. Is function K$($x$,$ z$)=$ c$1$K$1($x$,$ z$)+$ c$2$K$2($x$,$ z$)$ for c$1,$ c$2>0$ a kernel function? If your answer is yes, write down the corresponding $$ in terms of $1$ and $2.$ If not, provide a proof or explain why.