def _round(e, a, b):
c = a % b;
if e == 'round':
for i in [0, 1]:
if b / 2 * i <= c < b / 2 * (i + 1): return a - c + b * i;
if e == 'floor' and 0 <= c < b: return a - c;
if e == 'ceil' and 0 < c <= b: return a - c + b;