Revert "issue_5: Reject invalid input"

This reverts commit 8de9aa190c77c9b1349438bad8a94c59d5353c14.
Revert "Revert "issue_5: Reject invalid input""

This reverts commit 1d4a10e7c386d3a4577f5cfa136e87366480afcc.
issue_5: Added handling of quarter