new_contents: from ppb_vector import Vector2
  from math import isclose
  import pytest
  
  @pytest.mark.parametrize("left, right, expected", [
      (Vector2(1, 1), Vector2(0, -1), 135),
      (Vector2(1, 1), Vector2(-1, 0), 135),
      (Vector2(0, 1), Vector2(0, -1), 180),
      (Vector2(-1, -1), Vector2(1, 0), 135),
      (Vector2(-1, -1), Vector2(-1, 0), 45)
  ])
  def test_angle(left, right, expected):
      assert isclose(left.angle(right), expected)
      assert isclose(right.angle(left), expected)
  
subject: Add tests for angle