docs: def add_membership(self, name_or_org, role='member', **kwargs):
          """
              add a membership in an organization and return the membership
              object in case there are more details to add
          """
          if isinstance(name_or_org, Organization):
              membership = Membership(person_id=self._id,
                                      person_name=self.name,
                                      organization_id=name_or_org._id,
                                      role=role, **kwargs)
          else:
              membership = Membership(person_id=self._id,
                                      person_name=self.name,
                                      organization_id=_make_pseudo_id(name=name_or_org),
                                      role=role, **kwargs)
          self._related.append(membership)
          return membership