class Rugged::Repository

def diff_workdir(left, opts = {})
  left = rev_parse(left) if left.kind_of?(String)
  if !left.is_a?(Rugged::Tree) && !left.is_a?(Rugged::Commit)
    raise TypeError, "Expected a Rugged::Tree or Rugged::Commit instance"
  end
  left.diff_workdir(opts)
end