PyExpression () { List<PsiElement> exprs = findChildrenByType(PythonDialectsTokenSetProvider.getInstance().getExpressionTokens()); // normally there are 2 exprs, the second is the source. if (exprs.size() != 2) return null; // could be a parsing error PyExpression ret = (PyExpression)exprs.get(1); if (followsNodeOfType(ret.getNode(), PyTokenTypes.IN_KEYWORD)) return ret; else return null; }