Python binding for Syck, which, according is, according to the web site:

  Syck is an extension for reading and writing YAML swiftly in popular
  scripting languages. As Syck loads the YAML, it stores the data
  directly in your language's symbol table. This means speed. This
  means power. This means Do not disturb Syck because it is so focused
  on the task at hand that it will slay you mortally if you get in its
  way.

WWW: http://www.pyyaml.org/wiki/PySyck