Ambiguous error message loading error: cannot find URI [...]*workflow.yml*

[danikam]

The error message thrown here in raw_with_defaults.py is ambiguous in that it appears to get thrown in both of the following two situations:

1. The workflow.yml file actually doesn't exist at the specified location, or the authenticated user doesn't have permission to access it.
2. The workflow.yml file does exist and the authenticated user has permission to access it, but there's some syntax error in the file (eg. indentation) that prevents yadage from using it.

Perhaps a solution could be to have an initial check that the file actually exists and is accessible, and throw a file can't be accessed error in the event that it isn't, and then subsequently check if the file can be read in successfully with data = urlopen(uri).read(), and throw an error like file cannot be read - check yaml syntax if that check fails.