Function schedule 

pub(crate) fn schedule(
    effective: NaiveDate,
    termination: NaiveDate,
    frequency: Named<Period>,
    calendar: &PyCalendar,
    business_day_convention: Named<BusinessDayConvention>,
    roll_convention: Named<RollConvention>,
    stub: &str,
    end_of_month: bool,
    terminal_business_day_convention: Option<Named<BusinessDayConvention>>,
    date_generation: Option<&str>,
    first_regular_start: Option<NaiveDate>,
    last_regular_end: Option<NaiveDate>,
) -> PyResult<PySchedule>

Generates a calculation-period schedule.

The same generator every instrument’s accrual schedule is built by, so the boundaries this returns are the boundaries a trade on these terms accrues on.

effective and termination are unadjusted anchors, not the adjusted boundaries this returns. One of the two is the seed regular boundaries are measured from and the other is only a boundary, and which is which follows stub:

stub	seed	boundary only
"ShortFinal" / "LongFinal"	effective	termination
"ShortInitial" / "LongInitial"	termination	effective

Passing an already-adjusted date in place of the seed moves every interior boundary and raises nothing; in place of the other date it is harmless. Note that Calendar.advance adjusts, so resolving a tenor with it produces an adjusted termination — use the free add_period for an unadjusted one.

Holding only adjusted dates, pass the roll that generated them: roll snaps interior boundaries after generation and so supersedes the seed’s day of month. An adjusted effective of 2000-01-03 under roll="1" gives the same dates as the unadjusted 2000-01-01 under roll="None".

first_regular_start and last_regular_end state the stub dates (FpML’s firstRegularPeriodStartDate / lastRegularPeriodEndDate): the regular periods run between them, a front stub from effective and a back stub to termination; state both for a double stub. Either raises ValueError outside the term or out of order, and does not combine with date_generation="Cds".

To state boundary dates outright instead of generating them, use Schedule.from_dates, which applies no calendar, roll or adjustment at all.