[NguoiChauA]

I'm learning about Pawn language . I'm having trouble with parameters in the enum function

enum E_MY_TAG (<<= 1)
{
E_MY_TAG_NONE,
E_MY_TAG_VAL_1 = 1,
E_MY_TAG_VAL_2,
E_MY_TAG_VAL_3,
E_MY_TAG_VAL_4
}
new E_MY_TAG:gMyTagVar = E_MY_TAG_VAL_2 | E_MY_TAG_VAL_3;

I learned that the values in the enum will increment by default by +=1 and my lesson says the code :

new E_MY_TAG:gMyTagVar = E_MY_TAG_VAL_2 | E_MY_TAG_VAL_3;
That will create a new variable and assign it the value 6 (4 | 2)

I don't understand it , why the value of E_MY_TAG_VAL_2 is 4 and E_MY_TAG_VAL_3 is 2 and the parameter in the enum function why it is <<=1 , i remember there is no such operator . Thank you ^^