input: Write a function to calculate the area of a triangle given its three vertices.
  assert calculate_area_of_triangle((2, 0), (3, 4), (6, 2)) == 6.0
  assert calculate_area_of_triangle((0, 0), (0, 1), (1, 0)) == 0.5
  assert calculate_area_of_triangle((0, 0), (4, 0), (0, 3)) == 6.0
output: def calculate_area_of_triangle(vertex1, vertex2, vertex3):
      x1, y1 = vertex1
      x2, y2 = vertex2
      x3, y3 = vertex3
      return abs((x1*(y2 - y3) + x2*(y3 - y1) + x3*(y1 - y2)) / 2)