docs: public Object getSource(VariableScope variableScope) {
  
      if (sourceValueProvider instanceof ConstantValueProvider) {
        String variableName = (String) sourceValueProvider.getValue(variableScope);
  
        return variableScope.getVariableTyped(variableName);
      }
      else {
        return sourceValueProvider.getValue(variableScope);
      }
  
    }