Weierstrass M-test

Let $X$ be any set, ${\{f_n\}}_{n\in \mathbb{N}}$ a sequence of real or complex valued functions on $X$ and ${\{M_n\}}_{n\in \mathbb{N}}$ a sequence of non-negative real numbers.Suppose that, for each $n\in \mathbb{N}$ and $x\in X$, we have$|f_n(x)|\le M_n$. Then $f={\sum }_{n=1}^{\mathrm{\infty }}{f}_n$ converges uniformly if${\sum }_{n=1}^{\mathrm{\infty }}{M}_n$ converges.