def unlock_repo(self, repo_name):
assert isinstance(repo_name, (str, unicode)), repo_name<EOL>headers, data = self._requester.requestJsonAndCheck(<EOL>"<STR_LIT>",<EOL>self.url + "<STR_LIT>" + repo_name + "<STR_LIT>",<EOL>headers={<EOL>"<STR_LIT>": Consts.mediaTypeMigrationPreview<EOL>}<EOL>)<EOL>
:calls: `DELETE /user/migrations/:migration_id/repos/:repo_name/lock`_
:param repo_name: str
:rtype: None