class_docstr: Integer representing a zoom value allowed by Google Maps
class_docstr_tok: ["Integer","representing","a","zoom","value","allowed","by","Google","Maps"]
code: def validate(self, obj, value):
      if 0 <= value <= 21:
          return value
      else:
          self.error(obj, value)
  
imports: import re
  import traitlets
  from .locations import locations_to_list
label_desc: Use image node_id 1 for calling the ZoomLevel obj's underlying member method code with example usage: obj.validate(obj, value) and returns: value