static _getChildANInputElement(formNode) { //FIXME test this
        const inputList = formNode.getElementsByTagName('input');

        // Loop this list and keep only the inputs that are managed by AutoNumeric
        const autoNumericInputs = [];
        const inputElements = Array.prototype.slice.call(inputList, 0);
        inputElements.forEach(input => {
            if (this.test(input)) {
                autoNumericInputs.push(input);
            }
        });

        return autoNumericInputs;
    }
Return an array of autoNumeric elements, child of the <form> element passed as a parameter.

@param {HTMLElement} formNode
@returns {Array}
@private