code: public function load($filePath, $context)
      {
          $pattern = '/(msgctxt\s+"(.*?(?<!\\\\))")?\s+' // context
              . 'msgid\s+((?:".*(?<!\\\\)"\s*)+)\s+' // message ID, i.e. original string
              . 'msgstr\s+((?:".*(?<!\\\\)"\s*)+)/'; // translated string
          $content = file_get_contents($filePath);
          $matches = [];
          $matchCount = preg_match_all($pattern, $content, $matches);
  
          $messages = [];
          for ($i = 0; $i < $matchCount; ++$i) {
              if ($matches[2][$i] === $context) {
                  $id = $this->decode($matches[3][$i]);
                  $message = $this->decode($matches[4][$i]);
                  $messages[$id] = $message;
              }
          }
  
          return $messages;
      }
docs: Loads messages from a PO file.
  @param string $filePath file path
  @param string $context message context
  @return array message translations. Array keys are source messages and array values are translated messages:
  source message => translated message.