diff --git a/src/postprocessor/chainer.py b/src/postprocessor/chainer.py
index fb50c792805c04cfc42434558c35f9f1783da102..4b101922ee882744ee7d1e311a3b35bbe7f9bdec 100644
--- a/src/postprocessor/chainer.py
+++ b/src/postprocessor/chainer.py
@@ -4,7 +4,6 @@ import re
 import typing as t
 from copy import copy
 
-import numpy as np
 import pandas as pd
 
 from agora.io.signal import Signal