docs: public String getBusinessKey(VariableScope variableScope) {
      if (businessKeyValueProvider == null) {
        return null;
      }
  
      Object result = businessKeyValueProvider.getValue(variableScope);
  
      if (result != null && !(result instanceof String)) {
        throw new ClassCastException("Cannot cast '"+result+"' to String");
      }
  
      return (String) result;
    }