In the solution of an exercise, there is the following equality: $$ \sum_{-\infty}^{\infty} \delta(\theta - \frac{1}{4} - \frac{k}{2}) = \sum_{-\infty}^{\infty} \delta(\theta - \frac{1}{4} - k) + \sum_{-\infty}^{\infty} \delta(\theta - \frac{3}{4} - k)$$
I struggle to understand what property they used. I searched on the internet but did not find an explanation. May I ask you for help ?
Making the comment an answer: Just divide up the sum into its odd and even terms.