private static PsiMethodCallExpression findSingleCalledMethod(PsiExpression arg) {
      final PsiLambdaExpression lambda = tryCast(skipParenthesizedExprDown(arg), PsiLambdaExpression.class);
      if (lambda == null) return null;
      final PsiParameter[] parameters = lambda.getParameterList().getParameters();
      if (parameters.length != 1) return null;
      final PsiParameter parameter = parameters[0];
      final List<PsiReferenceExpression> references = VariableAccessUtils.getVariableReferences(parameter);
      if (references.size() != 1) return null;
      final PsiMethodCallExpression call = ExpressionUtils.getCallForQualifier(references.get(0));
      if (call == null || !call.getArgumentList().isEmpty()) return null;
      return call;
    }
private static PsiMethodCallExpression findSingleCalledMethod(PsiExpression arg)