Fix error message

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (f555e25) 92.41% compared to head (ad77184) 92.41%. Report is 1 commits behind head on dev.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #17 +/- ## ======================================= Coverage 92.41% 92.41% ======================================= Files 6 6 Lines 435 435 ======================================= Hits 402 402 Misses 33 33 ``` | Flag | Coverage Δ | | |---|---|---| | unittests | `92.41% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=biosimulators#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files Changed](https://app.codecov.io/gh/biosimulators/Biosimulators_tellurium/pull/17?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=biosimulators) | Coverage Δ | | |---|---|---| | [biosimulators\_tellurium/core.py](https://app.codecov.io/gh/biosimulators/Biosimulators_tellurium/pull/17?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=biosimulators#diff-Ymlvc2ltdWxhdG9yc190ZWxsdXJpdW0vY29yZS5weQ==) | `91.29% <ø> (ø)` | | | [biosimulators\_tellurium/\_version.py](https://app.codecov.io/gh/biosimulators/Biosimulators_tellurium/pull/17?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=biosimulators#diff-Ymlvc2ltdWxhdG9yc190ZWxsdXJpdW0vX3ZlcnNpb24ucHk=) | `100.00% <100.00%> (ø)` | |

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.