9. XOR Gate Using Basic Gates

How do you plan to solve it?

// ============================================================
// Basic Gates (given)
// ============================================================
module and_gate(input a, b, output y);
    assign y = a & b;
endmodule

module or_gate(input a, b, output y);
    assign y = a | b;

endmodule

module not_gate(input a, output y);
    assign y = !a;

endmodule

// ============================================================
// XOR Gate
// ============================================================
module xor_gate (
    input  a, b,
    output y
);
    wire o1, o2, o3, o4;

    not_gate n1(b, o1);
    and_gate a1(a, o1, o2);
    not_gate n2(a, o3);
    and_gate a2(o3, b, o4);
    or_gate o(o2, o4, y);

endmodule