fn verify_object(odb: &git2::Odb, oid: &Oid, expected: ObjectType) -> Result<(), error::Write> {
use git2::{Error, ErrorClass, ErrorCode};
let (_, _, kind) = odb
.reader(*oid)
let (_, kind) = odb
.read_header(*oid)
.map_err(|err| error::Write::OdbRead { oid: *oid, err })?;
if kind != expected {
Err(error::Write::NotCommit {