'Get an issue Resource from the server.
:param id: ID or key of the issue to get
:param fields: comma-separated string of issue fields to include in the results
:param expand: extra information to fetch inside each resource'

def issue(self, id, fields=None, expand=None):

    if isinstance(id, Issue):
        return id
    issue = Issue(self._options, self._session)
    params = {}
    if (fields is not None):
        params[u'fields'] = fields
    if (expand is not None):
        params[u'expand'] = expand
    issue.find(id, params=params)
    return issue
