diff --git a/Question_21_30/answers_py/answer_30.py b/Question_21_30/answers_py/answer_30.py
index 08ade59c..5783ec53 100644
--- a/Question_21_30/answers_py/answer_30.py
+++ b/Question_21_30/answers_py/answer_30.py
@@ -49,7 +49,7 @@ def affine(img, a, b, c, d, tx, ty):
 A = 30.
 theta = - np.pi * A / 180.
 
-out = affine(img, a=np.cos(theta), b=-np.sin(theta), c=np.sin(theta), d=np.cos(theta),
+out = affine(_img, a=np.cos(theta), b=-np.sin(theta), c=np.sin(theta), d=np.cos(theta),
  tx=0, ty=0)