def initialize(options={})
        raise ArgumentError,  "You must specify a year for date time grouping" unless options[:year]
        raise ArgumentError, "You must specify a date_time_grouping when creating a DateGroupItem for auto filter" unless options[:date_time_grouping]
        parse_options options
      end
Creates a new DateGroupItem
@param [Hash] options A hash of options to use when
instanciating the object
@option [String] date_time_grouping the part of the date this
filter should apply for grouping
@option [Integer|String] year @see year
@option [Integer] month @see month
@option [Integer] day @see day
@option [Integer] hour @see hour
@option [Integer] minute @see minute
@option [Integer] second @see second