code: protected function describeFloatDifference($first, $second, $identical)
      {
          if (is_object($second) || is_array($second)) {
              return $this->describeGenericDifference($first, $second);
          }
  
          return sprintf(
              'because [%s] differs from [%s] by %s',
              $this->describeValue($first),
              $this->describeValue($second),
              abs($first - $second)
          );
      }
docs: Creates a human readable description of the difference between
  two floating point numbers.
  
  @param float $first         First float.
  @param mixed $second        Float to compare with.
  @param bool $identical   If true then type anomolies count.
  
  @return string              Human readable description.