diff --git a/charon_vna/cli.py b/charon_vna/cli.py
index 5b49c92..f4fdf07 100644
--- a/charon_vna/cli.py
+++ b/charon_vna/cli.py
@@ -14,7 +14,7 @@ import click
 @click.option("--power", "-p", type=float, default=-5, help="Port output power [dBm].")
 @click.option("--snp", "-o", type=click.Path(), help="Path for output Touchstone file.")
 def capture(start: float, stop: float, pts: int, power: float, snp: Path, ports: int):
-    pass
+    raise NotImplementedError
 
 
 # %%
diff --git a/charon_vna/gui.py b/charon_vna/gui.py
index f00ceec..ac6af54 100644
--- a/charon_vna/gui.py
+++ b/charon_vna/gui.py
@@ -1,3 +1,4 @@
+# %% imports
 import sys
 from pathlib import Path
 from typing import Callable, List, Tuple
@@ -25,6 +26,7 @@ from charon_vna.util import db20, s2vswr
 
 # from vna import Charon
 
+# %%
 DEFAULT_CONFIG = dict(
     frequency=np.arange(1e9, 2e9, 11),  # Hz
     power=-5,  # dB
@@ -208,5 +210,6 @@ def main() -> None:
     app.exec()
 
 
+# %%
 if __name__ == "__main__":
     main()