diff --git a/dpdata/cp2k/output.py b/dpdata/cp2k/output.py
index 364593d5..135dd194 100644
--- a/dpdata/cp2k/output.py
+++ b/dpdata/cp2k/output.py
@@ -411,10 +411,10 @@ def get_frames(fname):
                 atom_symbol_list.append(ii.split()[3])
 
             # start to parse coords block
-            if "Atom  Kind  Element" in ii or "Atom Kind Element" in ii: 
+            if "Atom  Kind  Element" in ii or "Atom Kind Element" in ii:
                 coord_flag = True
-                coord_idx = idx  # save start line of coord block 
-            # parse coords lines 
+                coord_idx = idx  # save start line of coord block
+            # parse coords lines
             if coord_flag and idx > coord_idx:
                 if ii == "\n":
                     coord_flag = len(coord) == 0  # skip empty line at the beginning