edit func. descr.

cal_tools/cal_tools/tools.py

@@ -427,10 +427,11 @@ def get_notebook_name():
 
 def get_dir_creation_date(directory, run, tsdir=False):
     """
-    Return modification time of [directory]/[run]04
+    Return modification time of oldest file.h5 in [directory]/[run]04
 
     :param directory: path to directory which contains runs
     :param run: run number
+    :param tsdir: to get modification time of [directory]/[run]04.
     :return: (datetime) modification time
     """
     if tsdir: