fix doctest

Author: Davide-sd

spb/graphics/functions_3d.py

@@ -859,6 +859,9 @@ def implicit_3d(
     .. k3d-screenshot::
        :camera: 10.29, -15.33, -9.3, 0, 0, 0, 0.28, -0.41, 0.87
 
+       from sympy import *
+       from spb import *
+       var("x:z")
        graphics(
            implicit_3d(x*y*z < 1, (x, -5, 5), (y, -5, 5), (z, -5, 5), n=150),
            backend=KB
@@ -867,6 +870,9 @@ def implicit_3d(
     .. k3d-screenshot::
        :camera: -5.2, -1.86, 2.06, 0, 0.87, 0, 0.23, 0.16, 0.96
 
+       from sympy import *
+       from spb import *
+       var("x:z")
        graphics(
            implicit_3d(
                (x**2 + y**2 + z**2 >= 1) & (x**2 + y**2 + z**2 <= 3) & (y >= 0),

spb/plot_functions/functions_2d.py

@@ -430,7 +430,7 @@ def plot_parametric(*args, **kwargs):
        :include-source: True
 
        >>> from sympy import symbols, cos, sin, pi, floor, log
-       >>> from spb import plot_parametric
+       >>> from spb import plot_parametric, multiples_of_pi
        >>> t, u, v = symbols('t, u, v')
 
     A parametric plot of a single expression (a Hypotrochoid using an equal

spb/plot_functions/functions_3d.py

@@ -110,7 +110,7 @@ def plot3d_parametric_line(*args, **kwargs):
        ...     3 * sin(t) + 2 * sin(3 * t), cos(t) - 2 * cos(3 * t), cos(5 * t),
        ...     (t, 0, 2 * pi), "t [rad]", {"cmap": "hsv", "lw": 1.5},
        ...     aspect="equal",
-       ...     colorbar_ticks_formatter=multiples_of_pi_over_2()))
+       ...     colorbar_ticks_formatter=multiples_of_pi_over_2())
        Plot object containing:
        [0]: 3D parametric cartesian line: (3*sin(t) + 2*sin(3*t), cos(t) - 2*cos(3*t), cos(5*t)) for t over (0, 2*pi)
 
@@ -787,6 +787,9 @@ def plot3d_implicit(*args, **kwargs):
     .. k3d-screenshot::
        :camera: 10.29, -15.33, -9.3, 0, 0, 0, 0.28, -0.41, 0.87
 
+       from sympy import *
+       from spb import *
+       var("x:z")
        plot3d_implicit(
            x*y*z < 1, (x, -5, 5), (y, -5, 5), (z, -5, 5),
            n=150, backend=KB
@@ -795,6 +798,9 @@ def plot3d_implicit(*args, **kwargs):
     .. k3d-screenshot::
        :camera: -5.2, -1.86, 2.06, 0, 0.87, 0, 0.23, 0.16, 0.96
 
+       from sympy import *
+       from spb import *
+       var("x:z")
        plot3d_implicit(
            (x**2 + y**2 + z**2 >= 1) & (x**2 + y**2 + z**2 <= 3) & (y >= 0),
            (x, -2, 2), (y, -2, 2), (z, -2, 2),