code: public CacheCluster withSecurityGroups(SecurityGroupMembership... securityGroups) {
          if (this.securityGroups == null) {
              setSecurityGroups(new com.amazonaws.internal.SdkInternalList<SecurityGroupMembership>(securityGroups.length));
          }
          for (SecurityGroupMembership ele : securityGroups) {
              this.securityGroups.add(ele);
          }
          return this;
      }
docs: <p>
  A list of VPC Security Groups associated with the cluster.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setSecurityGroups(java.util.Collection)} or {@link #withSecurityGroups(java.util.Collection)} if you want
  to override the existing values.
  </p>
  
  @param securityGroups
  A list of VPC Security Groups associated with the cluster.
  @return Returns a reference to this object so that method calls can be chained together.