fix: createdAt should be optional field
Description
Make createdAt optional field, as it is not aways populated.
Related issues
Testing
Checklist
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I have updated the documentation (if necessary) -
I have added unit tests for new functionality (if applicable) -
My code follows the style guidelines of this project -
I have tested this code on my local machine before submitting this MR
Reviewers
Additional Notes
Closes #58 (closed)
Edited by Zdravko Iliev