def get_identities(self, item):
        """Return the identities from an item"""

        item = item['data']
        if 'owner' in item:
            owner = self.get_sh_identity(item['owner'])
            yield owner
        if 'user' in item:
            user = self.get_sh_identity(item['user'])
            yield user
        if 'mentor' in item:
            mentor = self.get_sh_identity(item['mentor'])
            yield mentor
Return the identities from an item