I'm using Redmine 2.5.2.
Tried to iterate over all issues for a given project with
for issue in rm.issue.filter(project_id='portal'):
but discovered that it returned open issues only.
In Docs it's not clear, which status or statuses are used by default in the above case.
Using
for issue in rm.issue.filter(project_id='portal', status_id='*'):
worked as approriate for me.