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