Proof: is the language $L_1$$=${$|$$\emptyset \subseteq L(M)$} (un)-decidable?


I want to show that $ L_1$ $ =$ {$ <M>|$ $ \emptyset \subseteq L(M)$ } is decidable/undecidable – without rice theorem (just for the case that I can apply it).

Every language contain the $ \emptyset$ as a subset. So my guess is that the language is decidable.

Therefore, let us assume that $ L_1$ is decidable. Lets say that $ N$ is the TM which decides $ L_1$ .

N = "with input $ <M>$ :"

How can I proof that $ N$ is a decider for $ L_1$ ?