'@type intervals: C{list} of C{int}, C{long}, or C{float} param
@param intervals: The intervals between instants.
@type default: C{int}, C{long}, or C{float}
@param default: The duration to generate if the intervals list
becomes empty.'

def __init__(self, intervals, default=60):

    self.intervals = intervals[:]
    self.default = default
