new_contents: class Triangle(object):
      number_of_sides = 3
      
      def __init__(self, angle1, angle2, angle3):
          self.angle1 = angle1
          self.angle2 = angle2
          self.angle3 = angle3
          
      def check_angles(self):
          if (self.angle1+self.angle2+self.angle3) == 180:
              return True
          else:
              return False
              
  my_triangle = Triangle(90, 30, 60)
  print my_triangle.number_of_sides
  print my_triangle.check_angles()
  
  class Equilateral(Triangle):
      angle = 60
      # means Equilateral is all the way same, so we don't need user to provide a arg
      def __init__(self):
          self.angle1 = 60
          self.angle2 = 60
          self.angle3 = 60
  
subject: Create Triangle.py