--- a/mercurial/cffi/osutilbuild.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/mercurial/cffi/osutilbuild.py	Sun Oct 06 09:45:02 2019 -0400
@@ -3,7 +3,9 @@
 import cffi
 
 ffi = cffi.FFI()
-ffi.set_source("mercurial.cffi._osutil", """
+ffi.set_source(
+    "mercurial.cffi._osutil",
+    """
 #include <sys/attr.h>
 #include <sys/vnode.h>
 #include <unistd.h>
@@ -19,8 +21,11 @@
     uint32_t          accessmask;
     off_t             datalength;
 } __attribute__((aligned(4), packed)) val_attrs_t;
-""", include_dirs=['mercurial'])
-ffi.cdef('''
+""",
+    include_dirs=['mercurial'],
+)
+ffi.cdef(
+    '''
 
 typedef uint32_t attrgroup_t;
 
@@ -96,7 +101,8 @@
 int close(int);
 
 #define O_RDONLY ...
-''')
+'''
+)
 
 if __name__ == '__main__':
     ffi.compile()