Modify the formula below so that it rounds to the nearest integer: df2['respiratory_rate'] = df2['respiratory_rate'].fillna( df2.groupby('pulse')['respiratory_rate'].transform('median'))

def round_up(x):
    if x - math.floor(x) < 0.5:
        return math.floor(x)
    return math.ceil(x)
    
df2['respiratory_rate'] = df2['respiratory_rate'].fillna(
                df2.groupby('pulse')['respiratory_rate'].transform(round_up))