What does `meta_network.py` and `old_meta_network.py` mean?

[dragen1860]

Dear author:
thanks for your great work on eager mode of gcn. However, i felt confused when i read on meta_network.py and old_meta_network.py files.
What do these two files do?

[hujunxianligong]

The old_meta_network.py is a backup file that I forgot to delete.
The meta_network contains some basic data structures for building graphs.