human
I am working on the file "18-05-28-Complete-Guide-to-Tensorflow-for-Deep-Learning-with-Python/01-Introduction-to-Neural-Networks/01_Neural Network From Scratch.ipynb".
The first task is:
Placeholders
Can you write Python code for it?
 What is a the Python code you requested?
assistant
#Here is the Python code you requested.

class Placeholder():
    """
    A placeholder is a node that needs to be provided a value for computing the output in the Graph.
    In case of supervised learning, X (input) and Y (output) will require placeholders.
    """
    def __init__(self):
        self.output_nodes = []
        _default_graph.placeholders.append(self)