docs: def bsfile(self, path):
          """Return a Build Source file ref, creating a new one if the one requested does not exist"""
          from sqlalchemy.orm.exc import NoResultFound
          from ambry.orm.exc import NotFoundError
  
          try:
  
              f =  object_session(self)\
                  .query(File)\
                  .filter(File.d_vid == self.vid)\
                  .filter(File.major_type == File.MAJOR_TYPE.BUILDSOURCE)\
                  .filter(File.path == path)\
                  .one()
  
              return f
  
          except NoResultFound:
              raise NotFoundError("Failed to find file for path '{}' ".format(path))