diff --git a/src/calibre/utils/imghdr.py b/src/calibre/utils/imghdr.py
index cceaf7879f..0179ad5bbc 100644
--- a/src/calibre/utils/imghdr.py
+++ b/src/calibre/utils/imghdr.py
@@ -2,9 +2,9 @@
 
 __all__ = ["what"]
 
-#-------------------------#
+# -------------------------#
 # Recognize image headers #
-#-------------------------#
+# -------------------------#
 
 def what(file, h=None):
     if h is None:
@@ -33,9 +33,9 @@ def what(file, h=None):
     return None
 
 
-#---------------------------------#
+# ---------------------------------#
 # Subroutines per image file type #
-#---------------------------------#
+# ---------------------------------#
 
 tests = []
 
@@ -132,9 +132,9 @@ def test_emf(h, f):
 
 tests.append(test_emf)
 
-#--------------------#
+# --------------------#
 # Small test program #
-#--------------------#
+# --------------------#
 
 def test():
     import sys