docs: def tree(self, subject_ids=None, visit_ids=None, **kwargs):
          """
          Return the tree of subject and sessions information within a
          project in the XNAT repository
  
          Parameters
          ----------
          subject_ids : list(str)
              List of subject IDs with which to filter the tree with. If
              None all are returned
          visit_ids : list(str)
              List of visit IDs with which to filter the tree with. If
              None all are returned
  
          Returns
          -------
          tree : arcana.repository.Tree
              A hierarchical tree of subject, session and fileset
              information for the repository
          """
          # Find all data present in the repository (filtered by the passed IDs)
          return Tree.construct(
              self, *self.find_data(subject_ids=subject_ids,
                                    visit_ids=visit_ids), **kwargs)