diff --git a/pdftools/cli.py b/pdftools/cli.py
index c00c5d0..81fafd4 100644
--- a/pdftools/cli.py
+++ b/pdftools/cli.py
@@ -66,13 +66,13 @@ def nameplates(attendees, logo, size, adjust_x, adjust_y):
     size and adjustment options.
     """
     if logo is not None:
-        logo = nameplate.Logo(logo, size * mm, adjust_x=adjust_x, adjust_y=adjust_y)
+        logo = nameplate.Logo(
+            logo, size * mm, adjust_x=adjust_x, adjust_y=adjust_y
+        )
     npc = nameplate.NamePlateCards(logo)
     npc.generate(attendees, show=True)
 
 
-
-
 @click.command()
 @click.argument(
     "pdf",
diff --git a/pdftools/formfill.py b/pdftools/formfill.py
index 49ebf5e..0be893b 100644
--- a/pdftools/formfill.py
+++ b/pdftools/formfill.py
@@ -1,11 +1,9 @@
 import pdfrw
 import subprocess
-import itertools
 import tempfile
 
 from pathlib import Path
 from reportlab.pdfgen import canvas
-from reportlab.lib.units import mm
 from reportlab.lib.pagesizes import A4
 
 
@@ -48,5 +46,3 @@ def fill(original_form, values, draw_function, output_file="filled.pdf"):
             # write the combined file to the output
             pdfrw.PdfWriter().write(output_file, form)
             subprocess.run(["open", output_file])
-
-
diff --git a/pdftools/nameplate.py b/pdftools/nameplate.py
index 334f0b0..5a54b79 100644
--- a/pdftools/nameplate.py
+++ b/pdftools/nameplate.py
@@ -41,6 +41,7 @@ false_and_true = itertools.cycle([False, True])
 
 imtek_logo_path = Path(__file__).parent / "logo_imtek.png"
 
+
 class NamePlateCards:
     def __init__(
         self,
diff --git a/pdftools/ruler.py b/pdftools/ruler.py
index 3b9020d..53ab79e 100644
--- a/pdftools/ruler.py
+++ b/pdftools/ruler.py
@@ -5,20 +5,19 @@ from . import formfill
 
 
 def ruler_overlay(original_form):
-
     def ruler(c, item):
         c.setStrokeColorRGB(0, 0, 1)
         c.setFillColorRGB(0, 0, 1)
         c.setLineWidth(0.5)
         c.setFont("Helvetica", 8)
-        x_grid = [x*mm for x in range(10, 210, 10)]
-        y_grid = [y*mm for y in range(10, 297, 10)]
+        x_grid = [x * mm for x in range(10, 210, 10)]
+        y_grid = [y * mm for y in range(10, 297, 10)]
         c.grid(x_grid, y_grid)
 
         for x in range(10, 210, 10):
-            c.drawString((x-2)*mm, 5*mm, str(x))
+            c.drawString((x - 2) * mm, 5 * mm, str(x))
         for y in range(10, 297, 10):
-            c.drawString(4*mm, (y-0.5)*mm, str(y))
+            c.drawString(4 * mm, (y - 0.5) * mm, str(y))
 
     ofp = Path(original_form)
     out_path = ofp.parent / f"{ofp.stem}_ruler.pdf"