def init(cls, typ, class2type):
        """
        Defines custom fields in the value factory so that the importer can find them
        @param typ
        @param class2type
        """
        field = typ.getField(cls.FIELD_NAME)
        class2type.put( StrStrHashMap , typ )
        typ.setComponentType( StrStrHashMap )
        typ.setImportExportHelper( StrStrHashMapSerializer(typ, field))
        typ.putValidator(field, Validator_object.get(1))
        typ.lock()
def git_checkout(git_url, git_branch=None, git_tag=None, git_hash=None):
    git_dst = tempfile.mkdtemp()
    g = GitManager(url=git_url, git_dst=git_dst, git_branch=git_branch, git_tag=git_tag, git_hash=git_hash)
    g.run()
    shutil.rmtree(git_dst)