fix bug, log warning it key does not exist

[mikecarr]

Description

Log warning if key does not exists instead of throwing and exception

Related Issue

This PR fixes or closes issue: fixes #22

Motivation and Context

How Has This Been Tested

Types of changes

• 🐛 Bug fix (non-breaking change which fixes an issue)
• 🚀 New feature (non-breaking change which adds functionality)
• 🌎 Translation (addition or update a translation)
• ⚙️ Tech (code style improvement, performance improvement or dependencies bump)
• 📚 Documentation (fix or addition in the documentation)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have tested the change locally.
• I followed the steps if I add a new language .