Amol/flatten nested filters

[amol21p]

Replace this text with a summary of the changes in your PR. The more detailed you are, the better.

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Before submitting the PR make sure the following are checked:

• [ ] The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• [ ] Wrote good commit messages.
• [ ] Commit message starts with [Fix #issue-number] (if the related issue exists).
• [ ] Feature branch is up-to-date with master (if not - rebase it).
• [ ] Squashed related commits together.
• [ ] Added tests.
• [ ] Added an entry to the changelog if the new code introduces user-observable changes. See changelog entry format for details.