code: private void updateCurrentFunction(AbstractFunctionExpression parentExpr) {
          GroovyExpression expr = parentExpr.getCaller();
          if (expr instanceof AbstractFunctionExpression) {
              AbstractFunctionExpression exprAsFunction = (AbstractFunctionExpression) expr;
              GroovyExpression exprCaller = exprAsFunction.getCaller();
              parentExpr.setCaller(exprCaller);
              updateCurrentFunctionDefintion(exprAsFunction);
          }
      }
docs: Adds the caller of parentExpr to the current body of the last
  function that was created.
  
  @param parentExpr