diff --git a/brainpy/_src/math/op_register/base.py b/brainpy/_src/math/op_register/base.py
index 40bd3212..e13382cb 100644
--- a/brainpy/_src/math/op_register/base.py
+++ b/brainpy/_src/math/op_register/base.py
@@ -128,7 +128,6 @@ def __init__(
     if gpu_kernel is None:
       gpu_checked = True
     elif isinstance(gpu_kernel, str): # cupy
-      # TODO: register cupy translation rule
       register_cupy_gpu_translation_rule(self.primitive, gpu_kernel)
       gpu_checked = True
     elif hasattr(gpu_kernel, '_is_wrapped_kernel') and gpu_kernel._is_wrapped_kernel:  # taichi