tracemalloc: filter_traces() raises a TypeError if filters is not an iterable

Lib/test/test_tracemalloc.py

@@ -346,6 +346,8 @@ class TestSnapshot(unittest.TestCase):
         self.assertIsNot(snapshot5.traces, snapshot.traces)
         self.assertEqual(snapshot5.traces, snapshot.traces)
 
+        self.assertRaises(TypeError, snapshot.filter_traces, filter1)
+
     def test_snapshot_group_by_line(self):
         snapshot, snapshot2 = create_snapshots()
         tb_0 = traceback_lineno('<unknown>', 0)

Lib/tracemalloc.py

@@ -1,4 +1,4 @@
-from collections import Sequence
+from collections import Sequence, Iterable
 from functools import total_ordering
 import fnmatch
 import linecache
@@ -382,6 +382,9 @@ class Snapshot:
         is a list of Filter instances.  If filters is an empty list, return a
         new Snapshot instance with a copy of the traces.
         """
+        if not isinstance(filters, Iterable):
+            raise TypeError("filters must be a list of filters, not %s"
+                            % type(filters).__name__)
         if filters:
             include_filters = []
             exclude_filters = []