# File lib/json-schema/schema.rb, line 36
    def self.stringify(schema)
      case schema
      when Hash then
        Hash[schema.map { |key, value| [key.to_s, stringify(schema[key])] }]
      when Array then
        schema.map do |schema_item|
          stringify(schema_item)
        end
      when Symbol then
        schema.to_s
      else
        schema
      end
    end