$\int _ { 0 } ^ { 20 \pi } ( | \sin x | + | \cos x | ) ^ { 2 } \, d x$ is equal to:\\ (1) $10 \pi + 4$\\ (2) $10 \pi + 2$\\ (3) $20 \pi - 2$\\ (4) $20 \pi + 2$