diff --git a/pdfplumber/cli.py b/pdfplumber/cli.py
index f6fbd07..95252b6 100644
--- a/pdfplumber/cli.py
+++ b/pdfplumber/cli.py
@@ -8,9 +8,8 @@ from typing import Any, DefaultDict, Dict, List
 
 from .pdf import PDF
 
-
 if len(sys.argv) == 1:
-    sys.argv.append('--help')
+    sys.argv.append("--help")
 
 
 def parse_page_spec(p_str: str) -> List[int]: