code: public com.google.api.ads.admanager.axis.v201902.CreativePlaceholder[] getBuiltInCreativePlaceholders() {
          return builtInCreativePlaceholders;
      }
docs: Gets the builtInCreativePlaceholders value for this ProposalLineItemConstraints.
  
  @return builtInCreativePlaceholders   * The built-in {@link CreativePlaceholder creative placeholders}
  for the created
  {@link ProposalLineItem}.
  
  <p>This attribute is read-only.