how to sort values of pandas dataframe for iqr

1    def mod_outlier(df):
2        df1 = df.copy()
3        df = df._get_numeric_data()
4
5
6        q1 = df.quantile(0.25)
7        q3 = df.quantile(0.75)
8
9        iqr = q3 - q1
10
11        lower_bound = q1 -(1.5 * iqr) 
12        upper_bound = q3 +(1.5 * iqr)
13
14
15        for col in col_vals:
16            for i in range(0,len(df[col])):
17                if df[col][i] < lower_bound[col]:            
18                    df[col][i] = lower_bound[col]
19
20                if df[col][i] > upper_bound[col]:            
21                    df[col][i] = upper_bound[col]    
22
23
24        for col in col_vals:
25            df1[col] = df[col]
26
27        return(df1)