Username responsible for ingesting this object into the repository,
        as recorded in the :attr:`audit_trail`, if available.

def ingest_user(self):
        '''Username responsible for ingesting this object into the repository,
        as recorded in the :attr:`audit_trail`, if available.'''
        # if there is an audit trail and it has records and the first
        # action is ingest, return the user
        if self.audit_trail and self.audit_trail.records \
           and self.audit_trail.records[0].action == 'ingest':
            return self.audit_trail.records[0].user