Please answer in OCaml.

In the lectures, we have seen examples of how to define a graph data structure by specifying only its edges. We can also similarly define a graph by specifying both its vertices and edges. For example, letg={nodes=[a;b;c;d];edges=[(d,c);(a,b);(a,c);(c,b)]};; 1. Write a function called paths that returns all simple paths (i.e., no repeated vertices) from a given node a to another given node b(=a) in a given graph g. Your function should return the list of all paths