diff --git a/list-generator/backend/app/services/pdf_generator.py b/list-generator/backend/app/services/pdf_generator.py
index d9141ad2..b4ab4093 100644
--- a/list-generator/backend/app/services/pdf_generator.py
+++ b/list-generator/backend/app/services/pdf_generator.py
@@ -5,7 +5,6 @@ from weasyprint import HTML
 import datetime
 
 def generate_school_pdf(institution: str, date_info: str, list_type: str, students_csv_path: str, families_csv_path: str = None, output_dir: str = "/tmp") -> str:
-    # Try different separators and encodings
     df = None
     for sep in [";", ","]:
         try:
@@ -15,13 +14,10 @@ def generate_school_pdf(institution: str, date_info: str, list_type: str, studen
                 break
         except Exception:
             continue
-
     if df is None:
         df = pd.read_csv(students_csv_path, sep=";", encoding="latin1")
-
     df.columns = df.columns.str.strip().str.replace("\"", "")
     print(f"Detected columns: {list(df.columns)}")
-
     col_mapping = {}
     for col in df.columns:
         lower_col = col.lower().strip()
@@ -31,30 +27,26 @@ def generate_school_pdf(institution: str, date_info: str, list_type: str, studen
             col_mapping[col] = "Nachname"
         elif lower_col in ["gruppe", "klasse", "group", "class"]:
             col_mapping[col] = "Klasse"
-
     df = df.rename(columns=col_mapping)
     df = df.fillna("")
-
     for col in ["Vorname", "Nachname", "Klasse"]:
         if col not in df.columns:
             df[col] = "Alle" if col == "Klasse" else ""
-
     df = df.sort_values(by=["Klasse", "Nachname", "Vorname"])
     grouped = df.groupby("Klasse")
     class_data = []
     for class_name, group in grouped:
         class_data.append({"name": class_name, "students": group.to_dict("records")})
-
     class_counts = [{"name": c, "count": len(g)} for c, g in grouped]
     total_students = len(df)
-
     template_dir = os.path.join(os.path.dirname(__file__), "..", "templates")
     env = Environment(loader=FileSystemLoader(template_dir))
     template = env.get_template("school_list.html")
     current_time = datetime.datetime.now().strftime("%d.%m.%Y %H:%M Uhr")
     html_out = template.render(institution=institution, date_info=date_info, class_counts=class_counts, total_students=total_students, class_data=class_data, current_time=current_time)
     clean_inst = institution.replace(" ", "_").replace("/", "-")
-    output_filename = f"Listen_{clean_inst}_{list_type}_{datetime.datetime.now().strftime(\"%Y-%m-%d_%H-%M\")}.pdf"
+    time_str = datetime.datetime.now().strftime("%Y-%m-%d_%H-%M")
+    output_filename = f"Listen_{clean_inst}_{list_type}_{time_str}.pdf"
     output_path = os.path.join(output_dir, output_filename)
     HTML(string=html_out).write_pdf(output_path)
     return output_path