when zmq error get empty date with empty constant

cal_tools/cal_tools/tools.py

@@ -486,10 +486,10 @@ def get_from_db(device, constant, condition, empty_constant,
     """
     from iCalibrationDB import ConstantMetaData, Versions
     import zmq
-    
+
     if version_info:
         meta_only = False
-    
+
     if device:
         metadata = ConstantMetaData()
         metadata.calibration_constant = constant
@@ -506,7 +506,7 @@ def get_from_db(device, constant, condition, empty_constant,
                                                     device=device,
                                                     start=creation_time)
         while ntries > 0:
-            
+
             this_interface = get_random_db_interface(cal_db_interface)
             try:
                 r = metadata.retrieve(this_interface, timeout=timeout,
@@ -533,7 +533,7 @@ def get_from_db(device, constant, condition, empty_constant,
                                                           begin_at))
             return constant.data, metadata
         else:
-            return empty_constant, metadata
+            return empty_constant, "empty"
     else:
         return empty_constant, None
 
@@ -562,7 +562,10 @@ def get_constant_from_db_and_time(device, constant, condition, empty_constant,
                           cal_db_interface, creation_time,
                           int(print_once), timeout, ntries)
     if m:
-        return data, m.calibration_constant_version.begin_at
+        if m == "empty":
+            return data, "00:00:00"            
+        else:
+            return data, m.calibration_constant_version.begin_at
     else:
         return data, None