diff --git a/src/allmydata/scripts/tahoe_status.py b/src/allmydata/scripts/tahoe_status.py
index a723274f0..75bc775f8 100644
--- a/src/allmydata/scripts/tahoe_status.py
+++ b/src/allmydata/scripts/tahoe_status.py
@@ -61,7 +61,7 @@ def _get_json_for_cap(options, cap):
         'uri/%s?t=json' % url_quote(cap),
     )
 
-def pretty_progress(percent, size=10, ascii=False):
+def pretty_progress(percent, size=10, output_ascii=False):
     """
     Displays a unicode or ascii based progress bar of a certain
     length. Should we just depend on a library instead?
@@ -72,7 +72,7 @@ def pretty_progress(percent, size=10, ascii=False):
     curr = int(percent / 100.0 * size)
     part = (percent / (100.0 / size)) - curr
 
-    if ascii:
+    if output_ascii:
         part = int(part * 4)
         part = '.oO%'[part]
         block_chr = '#'
diff --git a/src/allmydata/test/cli/test_status.py b/src/allmydata/test/cli/test_status.py
index 58818ed41..724661211 100644
--- a/src/allmydata/test/cli/test_status.py
+++ b/src/allmydata/test/cli/test_status.py
@@ -60,30 +60,30 @@ class FakeStatus(object):
 class ProgressBar(unittest.TestCase):
 
     def test_ascii0(self):
-        prog = pretty_progress(80.0, size=10, ascii=True)
+        prog = pretty_progress(80.0, size=10, output_ascii=True)
         self.assertEqual('########. ', prog)
 
     def test_ascii1(self):
-        prog = pretty_progress(10.0, size=10, ascii=True)
+        prog = pretty_progress(10.0, size=10, output_ascii=True)
         self.assertEqual('#.        ', prog)
 
     def test_ascii2(self):
-        prog = pretty_progress(13.0, size=10, ascii=True)
+        prog = pretty_progress(13.0, size=10, output_ascii=True)
         self.assertEqual('#o        ', prog)
 
     def test_ascii3(self):
-        prog = pretty_progress(90.0, size=10, ascii=True)
+        prog = pretty_progress(90.0, size=10, output_ascii=True)
         self.assertEqual('#########.', prog)
 
     def test_unicode0(self):
         self.assertEqual(
-            pretty_progress(82.0, size=10, ascii=False),
+            pretty_progress(82.0, size=10, output_ascii=False),
             u'\u2588\u2588\u2588\u2588\u2588\u2588\u2588\u2588\u258e ',
         )
 
     def test_unicode1(self):
         self.assertEqual(
-            pretty_progress(100.0, size=10, ascii=False),
+            pretty_progress(100.0, size=10, output_ascii=False),
             u'\u2588\u2588\u2588\u2588\u2588\u2588\u2588\u2588\u2588\u2588',
         )