code: def _validate_data(self, path, obj, _):
          
          errs = []
  
          if obj.type == None and getattr(obj, '$ref') == None:
              errs.append('type or $ref should be existed.')
  
          # make sure there is 'item' along with 'array'
          if not (obj.type == 'array') == (obj.items != None):
              errs.append('array should be existed along with items')
          if obj.uniqueItems != None and obj.type != 'array':
              errs.append('uniqueItems is only used for array type.')
  
          return path, obj.__class__.__name__, errs
docs: convert string value to integer/float value