From bbda76ff73b644f80eae04d05803c0fc11afed2e Mon Sep 17 00:00:00 2001
From: "W. Trevor King" <wking@drexel.edu>
Date: Sat, 6 Nov 2010 06:59:56 -0700
Subject: [PATCH] Ensure that self.headings exists in Histogram, e.g. in
 bell_rate.py's theory hist.

---
 pysawsim/histogram.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pysawsim/histogram.py b/pysawsim/histogram.py
index c0d73b7..7591e56 100644
--- a/pysawsim/histogram.py
+++ b/pysawsim/histogram.py
@@ -35,6 +35,9 @@ class Histogram (object):
 
     >>> h = Histogram()
     """
+    def __init__(self):
+        self.headings = None
+
     def calculate_bin_edges(self, data, bin_width):
         """
         >>> h = Histogram()
@@ -60,7 +63,6 @@ class Histogram (object):
         All bins should be of equal width (so we can calculate which
         bin a data point belongs to).
         """
-        self.headings = None
         data = numpy.array(data)
         self.bin_edges = numpy.array(bin_edges)
         bin_width = self.bin_edges[1] - self.bin_edges[0]
-- 
2.26.2