old_contents: from compiler import Compiler
  
  comp = Compiler()
  comp.ParseStatement("pequeno v lazo ^ !lazo -> (agua <-> liquido)")
  
  
  
new_contents: #!/usr/bin/python3
  from gui import InferenceSolver
  from PyQt5.QtCore import *
  from PyQt5.QtWidgets import *
  import sys
  
  app = QApplication(sys.argv)
  screen = InferenceSolver()
  screen.show()
  
  sys.exit(app.exec_())
  
subject: Add graphic interface to main program