public static List<LocalVariableDeclaration> variables(this MethodDeclaration methodDeclaration)
 {
     var astVisitors = new AstVisitors();
     methodDeclaration.AcceptVisitor(astVisitors, null);
     return astVisitors.localVariableDeclarations;
 }
 public static List<InvocationExpression> invocations(this MethodDeclaration methodDeclaration)
 {
     var astVisitors = new AstVisitors();
     methodDeclaration.AcceptVisitor(astVisitors, null);
     return astVisitors.invocationExpressions;
 }