def symbolize_config_value(key)
      value_str = @config.read(key).to_s
      if !value_str.nil? and !value_str.empty?
        value = value_str.upcase.to_sym
        @config.set(key, value)
      end
    end
def symbolize_config_value(key)
      value_str = @config.read(key).to_s
      if !value_str.nil? and !value_str.empty?
        value = value_str.upcase.to_sym
        @config.set(key, value)
      end
    end
Converts value of a config key to uppercase symbol.