docs: def _validate_resource_count(self):
          """ Specific validation for `resource_count` type
  
          The `resource_count` type works a little differently because it operates
          on the entire set of resources.  It:
            - does not require `key`
            - `value` must be a number
            - supports a subset of the OPERATORS list
          """
          for field in ('op', 'value'):
              if field not in self.data:
                  raise PolicyValidationError(
                      "Missing '%s' in value filter %s" % (field, self.data))
  
          if not (isinstance(self.data['value'], int) or
                  isinstance(self.data['value'], list)):
              raise PolicyValidationError(
                  "`value` must be an integer in resource_count filter %s" % self.data)
  
          # I don't see how to support regex for this?
          if self.data['op'] not in OPERATORS or self.data['op'] in {'regex', 'regex-case'}:
              raise PolicyValidationError(
                  "Invalid operator in value filter %s" % self.data)
  
          return self