fixed various typo's and duplicated use statements

This PR fixes a few typo's and some duplicated use statements in the recent exceptions related PR's

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| Refs tickets  | #1413
| License       | MIT
| Doc PR        |