Error when requesting Date fields in REST API

[Guy]

mistral --version: 3.0.0

When trying to perform a REST API GET call and specifying any date fields in the "fields" query param (i.e. created_at, updated_at) the request fails:

GET http://<ip>:8989/v2/executions/?fields=workflow_name,created_at

<error>
  <faultcode>Client</faultcode>
  <faultstring>
    Invalid input for field/attribute created_at. Value: '2017-02-22 12:33:49'. Wrong type. Expected '<type 'unicode'>', got '<type 'datetime.datetime'>'
  </faultstring>
  <debuginfo/>
</error>

When removing all date fields, the call works.

[Oleksiy Petrenko (enacero)]

I think the problem is in request url:
GOT: GET http://<ip>:8989/v2/executions/?fields=workflow_name,created_at
EXPECTED: GET http://<ip>:8989/v2/executions?fields=workflow_name,created_at
So last / before ? is not needed

[Oleksiy Petrenko (enacero)]

Sorry, That's not the solution.
Can't reproduce this error in devstack