code: @SuppressWarnings("unchecked")
    public Query where(String key, String value) {
      params.put(key, value);
      return (Query) this;
    }
docs: Simple `where` query.
  <p>
  This query will be used if there are not specialized queries available. Please use the more
  concrete methods in order to gain type safety and early exceptions, without requesting the API.
  
  @param key   the key to be added to the query.
  @param value the value to be added.
  @return the calling query for chaining.