add random seed

Author: LiamConnors

doc/python/selections.md

@@ -160,6 +160,7 @@ import plotly.graph_objects as go
 
 import numpy as np
 
+np.random.seed(0)
 t = np.linspace(-1, 1.2, 2000)
 x = (t**3) + (0.3 * np.random.randn(2000))
 y = (t**6) + (0.3 * np.random.randn(2000))