nltk/nltk — pull request #263 by oubiwann (2012-06-03 06:07:04+00:00)
Title: Added missing import for the demo.

When running nltk.grammar.sdg_demo() with the current git master (and with release 2.0.1), there is a traceback due to a missing import of DependencyGraph.

I initially tried adding the import at the top of the file, but it seems that there are some issues with cyclic imports/dependencies. As such, this change does adds the import in the one place where DependencyGraph is used, at the top of the sdg_demo function.