code: public void setCompanions(com.google.api.ads.admanager.axis.v201811.AdUnitSize[] companions) {
          this.companions = companions;
      }
docs: Sets the companions value for this AdUnitSize.
  
  @param companions   * The companions for this ad unit size.
  Companions are only valid if the environment is {@link
  EnvironmentType#VIDEO_PLAYER}.
  If the environment is {@link EnvironmentType#BROWSER}
  including companions
  results in an error.