def app_iter_range(self, seek=None, limit=None, block_size=None):
        """Iter over the content of the file.

        You can set the `seek` parameter to read the file starting from a
        specific position.

        You can set the `limit` parameter to read the file up to specific
        position.

        Finally, you can change the number of bytes read at once by setting the
        `block_size` parameter.
        """

        if block_size is None:
            block_size = BLOCK_SIZE

        if seek:
            self.file.seek(seek)
            if limit is None:
                limit -= seek
        try:
            while True:
                data = self.file.read(min(block_size, limit)
                                      if limit is not None
                                      else block_size)
                if not data:
                    return
                yield data
                if limit is not None:
                    limit -= len(data)
                    if limit <= 0:
                        return
        finally:
            self.file.close()
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/webob-1.2.3/webob/static.py/FileIter.app_iter_range/operator `is not` -> `is`