def method_missing(name, *args)
      value = @values[name]
      if value.nil? && !@values.has_key?(name)
        address = "<#{self.class.name}:0x00#{(self.object_id << 1).to_s(16)}>"
        raise NoMethodError.new("undefined method `#{name}' for ##{address}")
      end
      value
    end
def method_missing(name, *args)
      value = @values[name]
      if value.nil? && !@values.has_key?(name)
        address = "<#{self.class.name}:0x00#{(self.object_id << 1).to_s(16)}>"
        raise NoMethodError.new("undefined method `#{name}' for ##{address}")
      end
      value
    end
Fetch a configuration value.  The name must be a lowercase version of an
 uppercase name defined in the environment.  A NoMethodError is raised if
 no value matching the specified name is available.