code: public KieServerHttpRequest accept(final String accept ) {
          RequestInfo requestInfo = getRequestInfo();
          if( requestInfo.getHeader(ACCEPT).isEmpty() ) {
             requestInfo.setHeader(ACCEPT, new ArrayList<String>());
          }
          requestInfo.headers.get(ACCEPT).set(0, accept);
          return this;
      }
docs: Set the 'Accept' header to given value
  
  @param accept
  @return this request