The formatted data in file is similar to [YAML](http://en.wikipedia.org/wiki/YAML) and would like to create a grammer and parser for it. What is the easies way to do this in Python? Is there a tool that let you define a grammer for your data and parses according to the grammer?

P.S. I know the easier way to do this might be to change the data formate into JSON or other type but right now it can't be changed