Detect common type mistakes, and give useful feedback

[jaredoconnell]

Please describe what you would like to see in this project

One common mistake that several members of the team have made at some point is specifying a string instead of an enum value for a string-enum in the Python SDK. It would be useful to detect common type errors, like string for an enum, and specify that you need to reference the enum in code, not the string. Use the string in the YAML input only.