CFG visualizer crashes when creating file name for lambda

[mernst]

When running the CFG visualizer, I am encountering an error:
error: Unexpected AST kind: LAMBDA value.
In method dotOutputFileName, there are three possibilities for ast.getKind(). The code handles UnderlyingAST.Kind.ARBITRARY_CODE and UnderlyingAST.Kind.METHOD but not UnderlyingAST.Kind.LAMBDA.