code: public void setAliasAttributes(java.util.Collection<String> aliasAttributes) {
          if (aliasAttributes == null) {
              this.aliasAttributes = null;
              return;
          }
  
          this.aliasAttributes = new java.util.ArrayList<String>(aliasAttributes);
      }
docs: <p>
  Attributes supported as an alias for this user pool. Possible values: <b>phone_number</b>, <b>email</b>, or
  <b>preferred_username</b>.
  </p>
  
  @param aliasAttributes
  Attributes supported as an alias for this user pool. Possible values: <b>phone_number</b>, <b>email</b>,
  or <b>preferred_username</b>.
  @see AliasAttributeType