private static void registerClassAttributeReference(PsiReferenceRegistrar registrar,
                                                      final String name,
                                                      final PsiReferenceProvider provider) {
    registrar.registerReferenceProvider(psiElement(PyStringLiteralExpression.class)
                                          .withParent(psiElement(PySequenceExpression.class)
                                                        .with(Holder.IN_OPTIONAL_PARENTHESIS_INSIDE_ASSIGNMENT)
                                                        .inside(true, psiElement(PyAssignmentStatement.class)
                                                          .withFirstChild(psiElement(PyTargetExpression.class).withName(name)))), provider);
  }
private static void registerClassAttributeReference(PsiReferenceRegistrar registrar,
                                                      final String name,
                                                      final PsiReferenceProvider provider)