dicom time util is more robust if time field is missing

mu_map/file/dicom.py

@@ -69,8 +69,12 @@ class DICOMTime(Enum):
         """
         Get the datetime according to this DICOMTime type.
         """
-        _date = dicom[self.date_field()].value
-        _time = dicom[self.time_field()].value
+        try:
+            _date = dicom[self.date_field()].value
+            _time = dicom[self.time_field()].value
+        except:
+            return "               None"
+
         return datetime(
             year=int(_date[0:4]),
             month=int(_date[4:6]),