input: Write a python function to calculate the area of a triangle using the lengths of its sides.
  assert Triangle(2, 3, 4).area() == 2.9047
  assert Triangle(3, 4, 5).area() == 6.0000
output: import math
  
  class Triangle:
      def __init__(self, side1, side2, side3):
          self.side1 = side1
          self.side2 = side2
          self.side3 = side3
      
      def area(self):
          s = (self.side1 + self.side2 + self.side3) / 2
          area = math.sqrt(s * (s - self.side1) * (s - self.side2) * (s - self.side3))
          return round(area, 4)