add verbose info for Message.preview()

csst_common/pipeline.py

@@ -200,6 +200,10 @@ class Pipeline:
         """Move file `file_src` to `file_dist`."""
         shutil.copy(file_src, file_dst)
 
+    def copy_to_output(self, file_paths: list):
+        for file_path in file_paths:
+            pass
+
     def call(self, func: Callable, *args: Any, **kwargs: Any):
         self.pipeline_logger.info(
             f"====================================================="
@@ -301,10 +305,13 @@ class Message:
 
     def preview(self, dlist: list[dict], n: int = 10) -> None:
         """Preview top `n` messages."""
+        print(f"No. of messages = {len(dlist)}")
+        print(f"=========== Top {n} ===========")
         s = ""
         for d in dlist[:n]:
             s += self.dict2msg(d) + "\n"
         print(s)
+        print("")
 
     @staticmethod
     def dict2msg(d: dict):