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_to_nearest_integer(x):
    return round(x)
    
df2['respiratory_rate'] = df2['respiratory_rate'].fillna(
                df2.groupby('pulse')['respiratory_rate'].transform(round_to_nearest_integer))