theorem extracted_formal_statement_206.{u_1, w, u} {Ω : Type u} [inst : MeasurableSpace Ω] {Z : Type w} {n : ℕ}
  {ι : Type u_1} {f : ι → Z → ℝ} {μ : Measure Ω} [inst_1 : IsProbabilityMeasure μ] {X : Ω → Z} [inst_2 : Nonempty ι]
  [inst_3 : Countable ι] (hf : ∀ (i : ι), Measurable (f i ∘ X)) {b : ℝ} (hf' : ∀ (i : ι) (z : Z), |f i z| ≤ b)
  (ω' : Fin n → Ω) (i : ι)
  (h_original_goal :
    |∫ (x : Fin n → Ω), ∑ x, f i (X (ω' x)) - ∑ x_1, f i (X (x x_1)) ∂Measure.pi fun x => μ| ≤ ↑n * (b + b)) :
  (-(↑n * (b + b)) ≤ ∫ (x : Fin n → Ω), ∑ x, f i (X (ω' x)) - ∑ x_1, f i (X (x x_1)) ∂Measure.pi fun x => μ) ∧
    (∫ (x : Fin n → Ω), ∑ x, f i (X (ω' x)) - ∑ x_1, f i (X (x x_1)) ∂Measure.pi fun x => μ) ≤ ↑n * (b + b) := sorry

State before:
case hf.right.h.hf
Ω : Type u
inst✝¹ : MeasurableSpace Ω
Z : Type w
n : ℕ
ι : Type u_1
f : ι → Z → ℝ
μ : Measure Ω
inst✝ : IsProbabilityMeasure μ
X : Ω → Z
inst_2 : Nonempty ι
inst_3 : Countable ι
hf : ∀ (i : ι), Measurable (f i ∘ X)
b : ℝ
hf' : ∀ (i : ι) (z : Z), |f i z| ≤ b
ω' : Fin n → Ω
i : ι
⊢ |∫ (x : Fin n → Ω), ∑ x, f i (X (ω' x)) - ∑ x_1, f i (X (x x_1)) ∂Measure.pi fun x => μ| ≤ ↑n * (b + b)

Tactic: rw [abs_le]

State after:
[case hf.right.h.hf
 Ω : Type u
 inst✝¹ : MeasurableSpace Ω
 Z : Type w
 n : ℕ
 ι : Type u_1
 f : ι → Z → ℝ
 μ : Measure Ω
 inst✝ : IsProbabilityMeasure μ
 X : Ω → Z
 inst_2 : Nonempty ι
 inst_3 : Countable ι
 hf : ∀ (i : ι), Measurable (f i ∘ X)
 b : ℝ
 hf' : ∀ (i : ι) (z : Z), |f i z| ≤ b
 ω' : Fin n → Ω
 i : ι
 ⊢ (-(↑n * (b + b)) ≤ ∫ (x : Fin n → Ω), ∑ x, f i (X (ω' x)) - ∑ x_1, f i (X (x x_1)) ∂Measure.pi fun x => μ) ∧
     (∫ (x : Fin n → Ω), ∑ x, f i (X (ω' x)) - ∑ x_1, f i (X (x x_1)) ∂Measure.pi fun x => μ) ≤ ↑n * (b + b)]

Relevant lemmas:
abs_le : ∀ {G : Type u_1} [inst : LinearOrderedAddCommGroup G] {a b : G}, |a| ≤ b ↔ -b ≤ a ∧ a ≤ b