class TZInfo::AmbiguousTime

specifying how to resolve the ambiguity.
and {Timezone#period_for_local} when using an ambiguous time and not
{Timezone#local_time}, {Timezone#local_timestamp}, {Timezone#local_to_utc}
{AmbiguousTime} is raised by {Timezone#local_datetime},
when transitioning from daylight savings time to standard time.
clocks are set back in a time zone, most commonly during the repeated hour
than one possible equivalent UTC time. Such ambiguities arise when the
{AmbiguousTime} is raised to indicate that a specified local time has more