How to remove duplicate rows in pandas with concatenating column values?

Question

I want to remove duplicate rows from a CSV and concatenate the values of specific columns:

Input

    brand   code   des   attr_1   attr_2
0  brand1  code1  des1    attr1    attr1
1  brand2  code2          attr2       
2  brand3  code3  des3    attr3    attr3
3  brand1  code1          attr4       
4  brand3  code3  des7    attr33  attr33
5  brand1  code1          attr6       

Expected result:

    brand   code   des    attr_1                attr_2
0  brand1  code1  des1    attr1,attr4,attr6     attr1
1  brand2  code2          attr2       
2  brand3  code3  des3    attr3,attr33          attr3,attr3

Key columns are brand and code, columns that values should be concatenated are attr_1 and attr_2. Column des should have the value of first item met. Is it possible to make with pandas somehow?