Deprecate eval(), replacing it with lambda_eval() and unsafe_eval()

Tests/helper.py

@@ -115,7 +115,9 @@ def assert_image_similar(
 
     diff = 0
     for ach, bch in zip(a.split(), b.split()):
-        chdiff = ImageMath.eval("abs(a - b)", a=ach, b=bch).convert("L")
+        chdiff = ImageMath.lambda_eval(
+            lambda args: abs(args["a"] - args["b"]), a=ach, b=bch
+        ).convert("L")
         diff += sum(i * num for i, num in enumerate(chdiff.histogram()))
 
     ave_diff = diff / (a.size[0] * a.size[1])

Tests/test_image_reduce.py

@@ -186,7 +186,9 @@ def assert_compare_images(
 
     bands = ImageMode.getmode(a.mode).bands
     for band, ach, bch in zip(bands, a.split(), b.split()):
-        ch_diff = ImageMath.eval("convert(abs(a - b), 'L')", a=ach, b=bch)
+        ch_diff = ImageMath.lambda_eval(
+            lambda args: args["convert"](abs(args["a"] - args["b"]), "L"), a=ach, b=bch
+        )
         ch_hist = ch_diff.histogram()
 
         average_diff = sum(i * num for i, num in enumerate(ch_hist)) / (