diff -r 9cc55b743713 -r 57875cf423c9 mercurial/diffhelper.py
--- a/mercurial/diffhelper.py	Fri Oct 04 15:53:45 2019 -0400
+++ b/mercurial/diffhelper.py	Sat Oct 05 10:29:34 2019 -0400
@@ -14,6 +14,7 @@
     pycompat,
 )
 
+
 def addlines(fp, hunk, lena, lenb, a, b):
     """Read lines from fp into the hunk
 
@@ -47,6 +48,7 @@
                 b.append(s[1:])
                 a.append(s)
 
+
 def fixnewline(hunk, a, b):
     """Fix up the last lines of a and b when the patch has no newline at EOF"""
     l = hunk[-1]
@@ -62,6 +64,7 @@
         a[-1] = hline
     hunk[-1] = hline
 
+
 def testhunk(a, b, bstart):
     """Compare the lines in a with the lines in b