How to use the orbit-db-test-utils.MemStore function in orbit-db-test-utils

rmrf.sync(signingKeysPath)
      await fs.copy(identityKeyFixtures, identityKeysPath)
      await fs.copy(signingKeyFixtures, signingKeysPath)

      // Start two IPFS instances
      ipfs1 = await startIpfs(IPFS, ipfsConfig1)
      ipfs2 = await startIpfs(IPFS, ipfsConfig2)

      await connectPeers(ipfs1, ipfs2)

      // Get the peer IDs
      id1 = await getIpfsPeerId(ipfs1)
      id2 = await getIpfsPeerId(ipfs2)

      // Use mem-store for faster testing (no disk IO)
      const memstore = new MemStore()
      ipfs1.dag.put = memstore.put.bind(memstore)
      ipfs1.dag.get = memstore.get.bind(memstore)
      ipfs2.dag.put = memstore.put.bind(memstore)
      ipfs2.dag.get = memstore.get.bind(memstore)

      keystore = new Keystore(identityKeysPath)
      signingKeystore = new Keystore(signingKeysPath)

      // Create an identity for each peers
      testIdentity = await IdentityProvider.createIdentity({ id: 'userB', keystore, signingKeystore })
      testIdentity2 = await IdentityProvider.createIdentity({ id: 'userA', keystore, signingKeystore })
    })

rmrf.sync(ipfsConfig.repo)
      rmrf.sync(identityKeysPath)
      rmrf.sync(signingKeysPath)
      await fs.copy(identityKeyFixtures, identityKeysPath)
      await fs.copy(signingKeyFixtures, signingKeysPath)

      keystore = new Keystore(identityKeysPath)
      signingKeystore = new Keystore(signingKeysPath)

      testIdentity = await IdentityProvider.createIdentity({ id: 'userC', keystore, signingKeystore })
      testIdentity2 = await IdentityProvider.createIdentity({ id: 'userB', keystore, signingKeystore })
      testIdentity3 = await IdentityProvider.createIdentity({ id: 'userD', keystore, signingKeystore })
      testIdentity4 = await IdentityProvider.createIdentity({ id: 'userA', keystore, signingKeystore })
      ipfs = await startIpfs(IPFS, ipfsConfig)

      const memstore = new MemStore()
      ipfs.object.put = memstore.put.bind(memstore)
      ipfs.object.get = memstore.get.bind(memstore)
    })