// constructor
public Testbed(Set<CCGBankTaskSources> sourcesSet, File targetDirectory,
CCGBankTaskTestbed testbed) throws IOException {
grammarFile = new File(targetDirectory, "grammar.xml");
this.grammar = new Grammar(grammarFile.toURI().toURL(), true);
this.lexicon = grammar.lexicon;
this.rules = grammar.rules;
this.sourcesSet = sourcesSet;
this.targetDirectory = targetDirectory;