public static function resolve($key)
    {
        if ($key == 'B') return 0;
        $dict = static::$metric;
        if (preg_match(static::IEC_PATTERN, $key))
            $dict = static::$binary;
        if (array_key_exists($key, $dict)) return $dict[$key];
        throw new UnitNotFoundException(sprintf('Unit "%s" not found', $key));
    }
public static function resolve($key)
    {
        if ($key == 'B') return 0;
        $dict = static::$metric;
        if (preg_match(static::IEC_PATTERN, $key))
            $dict = static::$binary;
        if (array_key_exists($key, $dict)) return $dict[$key];
        throw new UnitNotFoundException(sprintf('Unit "%s" not found', $key));
    }
public static function resolve ( $ key ) { if ( $ key == 'B' ) return 0 ; $ dict = static :: $ metric ; if ( preg_match ( static :: IEC_PATTERN , $ key ) ) $ dict = static :: $ binary ; if ( array_key_exists ( $ key , $ dict ) ) return $ dict [ $ key ] ; throw new UnitNotFoundException ( sprintf ( 'Unit "%s" not found' , $ key ) ) ; }
Lookup the exponent based on prefix

@param $key
@throws UnitNotFoundException
@return int
Lookup the exponent based on prefix