Call to an undefined method Drupal\bootstrap_datetime_picker\Plugin\WebformElement\BootstrapDateTime::datePickerExists()

Problem/Motivation

Function called for Webform Element datePickerExists() is not defined anywhere.

Steps to reproduce

1. Enable this module.
2. Enable Webform module
3. Try to add a new element in a webform
4. Click "Add Element" and Choose "Bootstrap Date Time", it will through an AJAX error

Call to an undefined method                                                                    
         Drupal\bootstrap_datetime_picker\Plugin\WebformElement\BootstrapDateTime::datePickerExists().

Proposed resolution

Define the datePickerExists() function

Remaining tasks

Function definition

User interface changes

NA

API changes

NA

Data model changes

NA