code: def test_6_points_degree_3():
      d = 3
      X = [-1, 0, 2, 3, 9, 12]
      Y = [-4, 3, 3, 7, 9, 20]
      spline = interpolating_spline(d, x, X, Y)
  
      assert spline == Piecewise(
          (
              6058 * x**3 / 5301
              - 18427 * x**2 / 5301
              + x * Rational(12622, 5301)
              + 3,
              (x >= -1) & (x <= 2),
          ),
          (
              -8327 * x**3 / 5301
              + 67883 * x**2 / 5301
              - x * Rational(159998, 5301)
              + Rational(43661, 1767),
              (x >= 2) & (x <= 3),
          ),
          (
              5414 * x**3 / 47709
              - 1386 * x**2 / 589
              + x * Rational(4267, 279)
              - Rational(12232, 589),
              (x >= 3) & (x <= 12),
          ),
      )
  
file_path: sympy/sympy/functions/special/tests/test_bsplines.py
imports: from sympy.functions import bspline_basis_set, interpolating_spline
  from sympy.core.numbers import Rational
  from sympy.core.singleton import S
  from sympy.core.symbol import symbols
  from sympy.functions.elementary.piecewise import Piecewise
  from sympy.logic.boolalg import And
  from sympy.sets.sets import Interval
  from sympy.testing.pytest import slow
label_desc: Use image node_id 10 for calling a global function with example usage: test_6_points_degree_3() without return types