Rewrites an eval input_graph in place for simulated quantization.
The graph has fake quantization ops inserted to simulate the error introduced by quantization. Since the graph is transformed in place, the expected behavior of previously held references to nodes and tensors may change.
input_graph: The tf.Graph to be transformed, if None then defaults to the default graph.
ValueError: If elements contains an element that isn't a tf.Tensor or tf.Operation.