I want to call the method inside the same class. For example, when I click a button, it will trigger the method `handleLoginBtnClicked()`. I expect it will call the method `checkInputValidation()` in the same class. What is the proper way to do this?

```
export default class LoginCard extends React.Component {

    //If I click a button, this method will be called.
    handleLoginBtnClicked() {
        this.checkInputValidation();
    }

    checkInputValidation() {
        alert("clicked");
    }
    ...
    ...
    ...
    render() {
        ...
        <LoginBtn onClick={this.handleLoginBtnClicked}/>
        ...
    }
}

```

Error Message:

```
Uncaught TypeError: this.checkInputValidation is not a function

```