doc(yahoo#13): sample code to plot workflow diagram in intro

README.md

@@ -51,6 +51,19 @@ print(out)
 
 As you can see, any function can be used as an operation in GraphKit, even ones imported from system modules!
 
+As a debug aid, you may plot the workflow with one of these methods:
+
+```python
+   graph.net.plot(show=True)               # open a matplotlib window
+   graph.net.plot("path/to/workflow.png")  # supported files: .png .dot .jpg .jpeg .pdf .svg
+```
+
+> `graphviz` must be in your PATH, and `pydot` & `matplotlib` python packages installed.
+> You may install both when installing *graphkit* with its `plot` extras:
+> ```python
+> pip install graphkit[plot]
+> ```
+
 # License
 
 Code licensed under the Apache License, Version 2.0 license. See LICENSE file for terms.

docs/source/index.rst

@@ -69,6 +69,18 @@ Here's a Python script with an example GraphKit computation graph that produces
 
 As you can see, any function can be used as an operation in GraphKit, even ones imported from system modules!
 
+As a debug aid, you may plot the workflow with one of these methods::
+
+   graph.net.plot(show=True)               # open a matplotlib window
+   graph.net.plot("path/to/workflow.png")  # supported files: .png .dot .jpg .jpeg .pdf .svg
+
+.. NOTE:: 
+  `graphviz` must be in your PATH, and `pydot` & `matplotlib` python packages installed.
+  You may install both when installing *graphkit* with its `plot` extras::
+ 
+      pip install graphkit[plot]
+
+
 License
 -------