[Fix] Fix after iter SegVisualizationHook (#1908)

* [Fix] Fix after iter `SegVisualizationHook`

* ut

Author: MeowZheng

mmseg/engine/hooks/visualization_hook.py

@@ -62,12 +62,12 @@ def __init__(self,
                           'effect. The results will NOT be '
                           'visualized or stored.')
 
-    def after_iter(self,
-                   runner: Runner,
-                   batch_idx: int,
-                   data_batch: Sequence[dict],
-                   outputs: Sequence[SegDataSample],
-                   mode: str = 'val') -> None:
+    def _after_iter(self,
+                    runner: Runner,
+                    batch_idx: int,
+                    data_batch: Sequence[dict],
+                    outputs: Sequence[SegDataSample],
+                    mode: str = 'val') -> None:
         """Run after every ``self.interval`` validation iterations.
 
         Args:

tests/test_engine/test_visualization_hook.py

@@ -59,4 +59,4 @@ def test_after_test_iter(self):
         runner = Mock()
         runner.iter = 3
         hook = SegVisualizationHook(draw=True, interval=1)
-        hook.after_iter(runner, 1, self.data_batch, self.outputs)
+        hook.after_test_iter(runner, 1, self.data_batch, self.outputs)