ChecklistCombobox give the error in python

I am trying to use the ChecklistCombobox library in Python 3.12 but given the error at runtime

    cb = ChecklistCombobox(root,values=('1', '2', '3', '4'))         ^^^^^^^^^^^^^^^^^NameError: name 'ChecklistCombobox' is not defined

I am new to python

please send the full code for combobox with the checkbox