class_docstr: Handles searching a text widget for Find, Replace, and Grep.
code: def setpat(self, pat):
      self.patvar.set(pat)
  
imports: import re
  from tkinter import StringVar, BooleanVar, TclError
  from tkinter import messagebox
label_desc: Use image node_id 3 for calling the SearchEngine obj's underlying member method code with example usage: obj.setpat(pat) without return types