code: public AVQuery<T> whereNotEqualTo(String key, Object value) {
      conditions.whereNotEqualTo(key, value);
      return this;
    }
docs: Add a constraint to the query that requires a particular key's value to be not equal to the
  provided value.
  
  @param key The key to check.
  @param value The value that must not be equalled.
  @return Returns the query, so you can chain this call.