Redmine

I know the way to get all the users linked to a project, using the python-redmine package.

However, how do I get all the users registered in Redmine, even those who are not linked to any project?

rm_obj = Redmine(URL, username=user, password=redmine_password)
""" rm_obj is the redmine object """ 
user_resource = rm_obj.user.all()

user_out = dir(user_resource)
""" this has no attributes or methods that list all the users """ 

user_manager = user_resource.manager()

use_mgr_out = dir(user_manager)
""" this doesn't have attributes or methods that list all the users either """ 

(I have to use docstring rather than # because of the formatting problems)

Is there a method of an object that gives me all the users registered in redmine, even those users not linked to a project?