Using decimal package to fix rounding discrepancy issue

python_decimal_round_fix.py

from decimal import Decimal, ROUND_HALF_UP
# https://docs.python.org/3/library/functions.html#round
# https://support.office.com/en-us/f1/topic/csh?HelpId=xlmain11.chm60075&NS=MACEXCEL&Version=90&Lcid=1033&UiLcid=1033&EntryPoint=True
def round_fixed(value, digit):
    value_str = str(value)
    value_dec = Decimal(value_str)
    exp_unit = Decimal('0.1') ** digit
    mini_unit = Decimal('0.1') ** (digit + 1)
    if value_dec % exp_unit == (5 * mini_unit):
        value_dec += mini_unit
    result = Decimal(value_dec).quantize(exp_unit, rounding=ROUND_HALF_UP)
    return float(result)