added more date formats
This pull request **fixes 1 alert** when merging e6ae53a4b3dde3e74a3b34778b6a0ffcf50a81f8 into cc1553b253e9d17369c9771ccd1af196bfac70a5 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-f9683a00beb9844ce1192d72bb3702e9183e045d)

**fixed alerts:**

* 1 for Unused import This pull request **fixes 1 alert** when merging 85839109d19b8c09e818f096ca0660b9c22bc09f into cc1553b253e9d17369c9771ccd1af196bfac70a5 - [view on LGTM.com](https://lgtm.com/projects/g/NVIDIA/NeMo/rev/pr-7d08219436246b8357c295a4d6f5f684a6ce96d0)

**fixed alerts:**

* 1 for Unused import
Signed-off-by: Yang Zhang <yangzhang@nvidia.com>