Original error point：
results, err := e.BatchEnforce([[] []interface{}{"alice", "data1", "read"}, {"bob", datata2", "write"}, {"jack", "data3", "read"}})

Should be changed to:
results, err := e.BatchEnforce([][]interface{}{{"alice", "data1", "read"}, {"bob", "data2", "write"}, {"jack", "data3", "read"}})

a, err := xormadapter.NewAdapter("mysql", "mysql_username:mysql_password@tcp(127.0.0.1:3306)/casbin")

should be:
a, err := xormadapter.NewAdapter("mysql", "mysql_username:mysql_password@tcp(127.0.0.1:3306)/casbin", true)

postgresql casbin adaptor not working with postgres v7