code: def _call_to_base_type(self, value):
      
      methods = self._find_methods('_validate', '_to_base_type')
      call = self._apply_list(methods)
      return call(value)
docs: Call all _validate() and _to_base_type() methods on the value.
  
      This calls the methods in the method resolution order of the
      property's class.