code: def _ivy_jvm_options(self, repo):
      
      # Get authentication for the publish repo if needed.
      if not repo.get('auth'):
        # No need to copy here, as this list isn't modified by the caller.
        return self._jvm_options
  
      # Create a copy of the options, so that the modification is appropriately transient.
      jvm_options = copy(self._jvm_options)
      user = repo.get('username')
      password = repo.get('password')
      if user and password:
        jvm_options.append('-Dlogin={}'.format(user))
        jvm_options.append('-Dpassword={}'.format(password))
      else:
        raise TaskError('Unable to publish to {}. {}'
                        .format(repo.get('resolver'), repo.get('help', '')))
      return jvm_options
docs: Get the JVM options for ivy authentication, if needed.