How to use the graphql-tools.MockList function in graphql-tools

paginatedFriends: (o, { pageNo }) => {
        // console.log('pageNo: ', pageNo);
        return new MockList(pageNo * PAGE_SIZE, () => {
          return { id: casual.id, name: casual.name };
        });
      }
    };

allUsers: () => {
        const mockList = new MockList([USER_MIN_NUM, USER_MAX_NUM], (source, args, context, info) => {
          return { id: casual.id, name: casual.name };
        });
        // console.log('mockList: ', mockList);
        return mockList;
      },
      user: (source, { id }, context, info) => {

StandardSectionSlice: () => ({
            __typename: "LeadOneFullWidthSlice",
            items: new MockList(1)
          }),
          StandardSlice: () => ({

          someCs: () => new MockList(40),
        }),

list(_, { first }) {
                return new MockList(Math.min(count, first));
              }
            }

                topPosts: () => new MockList(topPostsLimit),
                User: () => ({

                topPosts: () => new MockList(topPostsLimit),
            }),

    contacts: () => new MockList(0),
  }),

    edges: () => new MockList(10),
  }),

  allGroups: () => new MockList(9),
  allProjectsInGroup: () => new MockList(5),