Let's be explicit with asserts; there was a bug in histogram

caused by assert foo when foo was an int with valid valid 0.

1 files changed, 4 insertions, 4 deletions

diff --git a/histogram.py b/histogram.py
index d45e93f..cea8b76 100644
--- a/histogram.py
+++ b/histogram.py
@@ -81,7 +81,7 @@ class SimpleHistogram(Generic[T]):
                 last_bucket_start = bucket[0]  # beginning of range
             if max_population is None or pop > max_population:
                 max_population = pop  # bucket with max items
-        if max_population is None:
+        if len(self.buckets) == 0 or max_population is None:
             return txt
 
         max_label_width: Optional[int] = None
@@ -100,9 +100,9 @@ class SimpleHistogram(Generic[T]):
                 max_label_width = label_width
             if start == last_bucket_start:
                 break
-        assert max_label_width
-        assert lowest_start
-        assert highest_end
+        assert max_label_width is not None
+        assert lowest_start is not None
+        assert highest_end is not None
 
         sigma_label = f'[{label_formatter}..{label_formatter}): ' % (
             lowest_start,