Get change log between 2 refs
        :param project:
        :param repository:
        :param ref_from:
        :param ref_to:
        :param limit: OPTIONAL: The limit of the number of changes to return, this may be restricted by
                fixed system limits. Default by built-in method: 99999
        :return:

def get_changelog(self, project, repository, ref_from, ref_to, limit=99999):
        """
        Get change log between 2 refs
        :param project:
        :param repository:
        :param ref_from:
        :param ref_to:
        :param limit: OPTIONAL: The limit of the number of changes to return, this may be restricted by
                fixed system limits. Default by built-in method: 99999
        :return:
        """
        url = 'rest/api/1.0/projects/{project}/repos/{repository}/compare/commits'.format(project=project,
                                                                                          repository=repository)
        params = {}
        if ref_from:
            params['from'] = ref_from
        if ref_to:
            params['to'] = ref_to
        if limit:
            params['limit'] = limit
        return (self.get(url, params=params) or {}).get('values')