R7:=IntegerRing(7);
GL7:=GeneralLinearGroup(2,R7);
H:=sub<GL7|[0,1,1,0],[2,0,0,1]>;
SubH:=Subgroups(H: IndexEqual:=3);
S2:=SubH[2]`subgroup;
ClassS2:=Class(GL7,S2);
ClassS2;