def include?(other)
      raise(ISO8601::Errors::TypeError, "The parameter must respond_to #to_time") \
        unless other.respond_to?(:to_time)

      (first.to_time <= other.to_time &&
       last.to_time >= other.to_time)
    end
def include?(other)
      raise(ISO8601::Errors::TypeError, "The parameter must respond_to #to_time") \
        unless other.respond_to?(:to_time)

      (first.to_time <= other.to_time &&
       last.to_time >= other.to_time)
    end
Check if a given time is inside the current TimeInterval.

 @param [#to_time] other DateTime to check if it's
   inside the current interval.

 @raise [ISO8601::Errors::TypeError] if time param is not a compatible
   Object.

 @return [Boolean]