diff --git a/setup.py b/setup.py
index 4fab496..e4959ec 100644
--- a/setup.py
+++ b/setup.py
@@ -32,7 +32,7 @@ setup(
 	license = 'MIT',
 	keywords = 'sequence-alignment',
 	scripts = ['python/minimap2.py'],
-        ext_modules = [Extension('mappy',
+	ext_modules = [Extension('mappy',
 		sources = ['python/mappy.pyx', 'align.c', 'bseq.c', 'chain.c', 'format.c', 'hit.c', 'index.c', 'pe.c', 'options.c',
 				   'ksw2_extd2_sse.c', 'ksw2_exts2_sse.c', 'ksw2_extz2_sse.c', 'ksw2_ll_sse.c',
 				   'kalloc.c', 'kthread.c', 'map.c', 'misc.c', 'sdust.c', 'sketch.c', 'esterr.c', 'splitidx.c'],
@@ -52,4 +52,4 @@ setup(
 		'Programming Language :: Python :: 3',
 		'Intended Audience :: Science/Research',
 		'Topic :: Scientific/Engineering :: Bio-Informatics'],
-        setup_requires=["cython"])
+	setup_requires=["cython"])