for (Sexp)

    # File lib/sexp.rb, line 27
      def self.for(klass, method = nil, walk_ancestors = false)
        require 'parse_tree'
        sexp = if walk_ancestors and method then
                 klass.ancestors.each do |klass|
                   sexp = ParseTree.translate klass, method
                   break sexp unless sexp == [nil]
                 end
               else
                 ParseTree.translate klass, method
               end

        Sexp.from_array sexp
      end