Deployer\Server\Configuration::setPemFile PHP Method

    public function setPemFile($pemFile)
    {
        $this->pemFile = $this->parseHome($pemFile);
        return $this;
    }

 /**
  * Authenticate with pem file
  *
  * @param string $pemFile
  *
  * @return Builder
  */
 public function pemFile($pemFile)
 {
     $this->config->setAuthenticationMethod(Configuration::AUTH_BY_PEM_FILE);
     $this->config->setPemFile($pemFile);
     return $this;
 }