input: Write a python function to create a DigitalClock class with methods to set time, get time, and display the time.
  assert my_clock.get_time() == (12, 45, 10)
  my_clock.set_time(5, 30, 25)
  assert my_clock.get_time() == (5, 30, 25)
  my_clock.set_time(0, 0, 0)
  assert my_clock.get_time() == (0, 0, 0)
output: class DigitalClock:
      def __init__(self):
          self.hours = 0
          self.minutes = 0
          self.seconds = 0
  
      def set_time(self, hours, minutes, seconds):
          self.hours = hours
          self.minutes = minutes
          self.seconds = seconds
  
      def get_time(self):
          return (self.hours, self.minutes, self.seconds)
  
      def display_time(self):
          return f"{self.hours:02}:{self.minutes:02}:{self.seconds:02}"
  
  # Test cases
  my_clock = DigitalClock()
  my_clock.set_time(12, 45, 10)
  assert my_clock.get_time() == (12, 45, 10)
  my_clock.set_time(5, 30, 25)
  assert my_clock.get_time() == (5, 30, 25)
  my_clock.set_time(0, 0, 0)
  assert my_clock.get_time() == (0, 0, 0)