I'm getting the error "The role defined for the function cannot be assumed by Lambda" when I'm trying to create a lambda function with create-function command.

aws lambda create-function
  --region us-west-2
  --function-name HelloPython
  --zip-file fileb://hello_python.zip
  --role arn:aws:iam::my-acc-account-id:role/default
  --handler hello_python.my_handler
  --runtime python2.7
  --timeout 15
  --memory-size 512
I had this error simply because I had a typo in the role ARN. I really wish the error was more explicit and said something along the lines of "this role doesn't exist", but alas.
The role defined for the function cannot be assumed by Lambda