code: public function sendDocument($peer, $mediaUri, $cleanUp = false)
      {
          $peer = $this->escapePeer($peer);
  
          //Process the requested media file.
          $processedMedia = $this->processMediaUri($mediaUri);
          if ( ! $processedMedia) {
              return false;
          }
  
          //Send media file.
          $result = $this->exec('send_document ' . $peer . ' ' . $processedMedia['filepath']);
  
          if ($cleanUp) {
              //Clean up if media file came from REMOTE address
              $this->cleanUpMedia($processedMedia);
          }
  
          return $result;
      }
docs: Sends a Document to $peer
  
  @param string $peer
  @param string $mediaUri Either a URL or a local filename of the media you wish to send
  @param bool   $cleanUp
  @return bool
  @uses exec()
  @uses escapePeer()
  @uses escapeStringArgument()