Do Not Exit With Non-Tradable Assets

[AlexCatarino]

Expected Behavior

"No security definition" doesn't raise an exception for non-tradable asset.

Any symbol ending in "..CNT" represents a non-tradable Escrow entitlement (potential future distribution) resulting from a corporation action, for which there is no ETA on a payment (if any) and any updates regarding the situation would be announced by the company and/or their transfer agent. Holders must retain the position in the account until the position allocation is made (if any further adjustments are needed) or until the position is removed as worthless by the Depository.

Actual Behavior

If the account has ..CNT assets, it exists.

Potential Solution

If we can't find the security definition, check for CNT and ignore it.

Reproducing the Problem

N/A

Checklist

• I have completely filled out this template
• I have confirmed that this issue exists on the current master branch
• I have confirmed that this is not a duplicate issue by searching issues
• I have provided detailed steps to reproduce the issue