190: replace and rewrite assert statements in non-test files.

[RasikaTelase]

This PR refactors non-test code by replacing all usage of assert statements
with proper error handling or conditional checks.

Purpose:

• Improves code reliability and prevents unexpected termination in production.

Scope:

• No changes to test files.
• Affects only logic files using assert.

Let me know if further changes are needed!

[RasikaTelase]

Refactored assert statements in non-test files for better error handling. Let me know if any changes or improvements are needed.