code: protected function describeGenericDifference($first, $second)
      {
          return sprintf(
              'as [%s] does not match [%s]', $this->describeValue($first), $this->describeValue($second)
          );
      }
docs: Creates a human readable description of the difference between two variables.
  The minimal version.
  
  @param null $first          First value.
  @param mixed $second        Value to compare with.
  
  @return string              Human readable description.