Fix dumb mistake

specs/_features/eip7594/polynomial-commitments-sampling.md

@@ -247,8 +247,8 @@ def add_polynomialcoeff(a: PolynomialCoeff, b: PolynomialCoeff) -> PolynomialCoe
  """
  Sum the coefficient form polynomials ``a`` and ``b``.
  """
- length_a, length_b = len(a), len(b)
  a, b = (a, b) if length_a >= length_b else (b, a)
+ length_a, length_b = len(a), len(b)
  return PolynomialCoeff([a[i] + (b[i] if i < length_b else BLSFieldElement(0)) for i in range(length_a)])
 ```