graph.get_tensor_by_name(output_str)

This line of code retrieves a tensor from the TensorFlow graph by its name.

The `get_tensor_by_name` method is called on the `graph` object and takes a single argument, `output_str`, which is a string representing the name of the tensor to retrieve.

The returned value is the tensor object itself, which can then be used to perform operations or feed data into the graph.