use an extractor class as ancestor of all extractors
treef05813ec23549e02c45305d61c0fc234db1008e2
-rw-r--r-- 407 MANIFEST
-rw-r--r-- 290 META.yml
-rw-r--r-- 299 Makefile.PL
-rw-r--r-- 4761 NEWS
-rw-r--r-- 19666 README
drwxr-xr-x - examples
-rw-r--r-- 7860 graph-includes
drwxr-xr-x - lib