Fix layout shape line dash w/ custom lenghts plotly#3375

Author: dvd7587

packages/python/plotly/plotly/validators/layout/shape/line/_dash.py

@@ -1,7 +1,7 @@
 import _plotly_utils.basevalidators
 
 
-class DashValidator(_plotly_utils.basevalidators.StringValidator):
+class DashValidator(_plotly_utils.basevalidators.DashValidator):
     def __init__(self, plotly_name="dash", parent_name="layout.shape.line", **kwargs):
         super(DashValidator, self).__init__(
             plotly_name=plotly_name,