@Nullable
  private static ChainCompletionContext extractContextFromReturn(PsiReturnStatement returnStatement,
                                                                 CompletionParameters parameters) {
    PsiType type = PsiTypesUtil.getMethodReturnType(returnStatement);
    if (type == null) return null;
    return ChainCompletionContext.createContext(type, returnStatement, suggestIterators(parameters));
  }
@Nullable
  private static ChainCompletionContext extractContextFromReturn(PsiReturnStatement returnStatement,
                                                                 CompletionParameters parameters)