parameters = [

    Parameter(

        name='gross_interest_rate',

        shape=NumberShape(

            kind=NumberKind.PERCENTAGE, min_value=0, max_value=1, step=0.01),

        level=Level.TEMPLATE,

        description='Gross Interest Rate',

        display_name='Rate paid on positive balances',

    ),

]

def _accrue_interest(vault, end_of_day_datetime):

    denomination = vault.get_parameter_timeseries(name='denomination').latest()

    # Get the balance at the end of the previous day

    balances = vault.get_balance_timeseries().at(timestamp=end_of_day_datetime)

    effective_balance = balances[(DEFAULT_ADDRESS, DEFAULT_ASSET, denomination, Phase.COMMITTED)].net

    gross_interest_rate = vault.get_parameter_timeseries(

        name='gross_interest_rate'

    ).before(timestamp=end_of_day_datetime)

    daily_rate = gross_interest_rate / 365

    daily_rate_percent = daily_rate * 100

    amount_to_accrue = _precision_accrual(effective_balance * daily_rate)

    # Your code goes here.

def _precision_accrual(amount):

    return amount.copy_abs().quantize(Decimal('.00001'), rounding=ROUND_HALF_UP)

​