Revert "PM-753: updated Regex class"

This reverts commit 8306afe859b3e73b686bc594b20c633611aa057d.
Revert "PM-753: updated test case"

This reverts commit 4a738db03bce92bb2ac2a77aa2d2dcd00c746926.
Revert "PM-753: Added pool attribute as first class element"

This reverts commit 204b88427c647da039612793aafd4100a90803b5.
PM-753 and PM-759