JavaScript: Jest doesn't recognise static functions

I'm following a tutorial which is using jest to test the javascript. The instructor created a static function called genesis() on a class called Block and it worked for him just fine, but when I tried to do it I got TypeError: block.genesis is not a function. If I remove the static keyword it recognises the function and the test passes.

Here is the class:

const { GENESIS_DATA } = require('./config');

class Block {
    constructor({ timestamp, lastHash, hash, data }) {
        this.timestamp = timestamp;
        this.lastHash = lastHash;
        this.hash = hash;
        this.data = data;
    }

    static genesis() {
        return new Block(GENESIS_DATA);
    }
}

module.exports = Block;

And the test:

const Block = require('./block');
const { GENESIS_DATA } = require('./config');

describe('Block', () => {
    const timestamp = 'a-date';
    const lastHash = 'a-hash';
    const hash = 'another-hash';
    const data = ['blockchain', 'data'];
    const block = new Block({ timestamp, lastHash, hash, data });

    describe('genesis()', () => {
        const genesisBlock = block.genesis();

        it('returns a block instance', () => {
            expect(genesisBlock instanceof Block).toBe(true);
        });

        it('returns the genesis data', () => {
            expect(genesisBlock).toEqual(GENESIS_DATA);
        });
    });
});