code: def test_is_parallel():
      p1 = Point3D(0, 0, 0)
      p2 = Point3D(1, 1, 1)
      p3 = Point3D(x1, x1, x1)
  
      l2 = Line(Point(x1, x1), Point(y1, y1))
      l2_1 = Line(Point(x1, x1), Point(x1, 1 + x1))
  
      assert Line.is_parallel(Line(Point(0, 0), Point(1, 1)), l2)
      assert (
          Line.is_parallel(l2, Line(Point(x1, x1), Point(x1, 1 + x1)))
          is False
      )
      assert Line.is_parallel(l2, l2.parallel_line(Point(-x1, x1)))
      assert Line.is_parallel(l2_1, l2_1.parallel_line(Point(0, 0)))
      assert Line3D(p1, p2).is_parallel(Line3D(p1, p2))  # same as in 2D
      assert (
          Line3D(Point3D(4, 0, 1), Point3D(0, 4, 1)).is_parallel(
              Line3D(Point3D(0, 0, 1), Point3D(4, 4, 1))
          )
          is False
      )
      assert Line3D(p1, p2).parallel_line(p3) == Line3D(
          Point3D(x1, x1, x1), Point3D(x1 + 1, x1 + 1, x1 + 1)
      )
      assert Line3D(p1, p2).parallel_line(p3.args) == Line3D(
          Point3D(x1, x1, x1), Point3D(x1 + 1, x1 + 1, x1 + 1)
      )
      assert (
          Line3D(Point3D(4, 0, 1), Point3D(0, 4, 1)).is_parallel(
              Line3D(Point3D(0, 0, 1), Point3D(4, 4, 1))
          )
          is False
      )
  
imports: from sympy.core.numbers import Float, Rational, oo, pi
  from sympy.core.relational import Eq
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol, symbols
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import acos, cos, sin
  from sympy.sets import EmptySet
  from sympy.simplify.simplify import simplify
  from sympy.functions.elementary.trigonometric import tan
  from sympy.geometry import Circle, GeometryError, Line, Point, Ray, Segment, Triangle, intersection, Point3D, Line3D, Ray3D, Segment3D, Point2D, Line2D, Plane
  from sympy.geometry.line import Undecidable
  from sympy.geometry.polygon import _asa
  from sympy.utilities.iterables import cartes
  from sympy.testing.pytest import raises, warns
label_desc: Use image node_id 23 for calling a global function with example usage: test_is_parallel() without return types