code: def get_details(self):
          
  
          # create the exception main message according to the type of result
          if isinstance(self.validation_outcome, Exception):
  
              prefix = 'Validation function [{val}] raised ' if self.display_prefix_for_exc_outcomes else ''
  
              # new: we now remove  "Root validator was [{validator}]", users can get it through e.validator
              contents = ('Error validating {what}. ' + prefix + '{exception}: {details}')\
                           .format(what=self.get_what_txt(),
                                   val=self.validator.get_main_function_name(),
                                   exception=type(self.validation_outcome).__name__,
                                   details=end_with_dot(str(self.validation_outcome)))
  
          else:
              contents = 'Error validating {what}: validation function [{val}] returned [{result}].' \
                         ''.format(what=self.get_what_txt(), val=self.validator.get_main_function_name(),
                                   result=self.validation_outcome)
  
          # return 'Wrong value: [{}]'.format(self.var_value)
          return contents
docs: The function called to get the details appended to the help message when self.append_details is True