class_docstr: Handles searching a text widget for Find, Replace, and Grep.
code: def isre(self):
      return self.revar.get()
  
imports: import re
  from tkinter import StringVar, BooleanVar, TclError
  from tkinter import messagebox
label_desc: Use image node_id 4 for calling the SearchEngine obj's underlying member method code with example usage: obj.isre() and returns: self