input: Write a python function to calculate the area and check if a triangle is equilateral.
  assert Triangle(3, 3, 3).get_area() == 3.897114317029974
  assert Triangle(3, 3, 3).is_equilateral() == True
  assert Triangle(5, 12, 13).get_area() == 30.0
  assert Triangle(5, 12, 13).is_equilateral() == False
output: import math
  
  class Triangle:
      def __init__(self, a, b, c):
          self.a = a
          self.b = b
          self.c = c
      
      def get_area(self):
          s = (self.a + self.b + self.c) / 2
          return math.sqrt(s * (s - self.a) * (s - self.b) * (s - self.c))
      
      def is_equilateral(self):
          return self.a == self.b == self.c