Amazon web services .StartExecution不是一个函数

我已经创建了一个lambda（到目前为止还不错）

规格：

• 有权使用STEP功能
• 流畅
• 版本：Node.js 14.x

但当我尝试从lambda调用step函数时，如下所示：

var AWS = require("aws-sdk");
var stepfunctions = new AWS.StepFunctions({apiVersion: '2016-11-23'});
const params = {
  "input": "{}",
  "name": srcKey,
  "stateMachineArn": process.env.STATE_MACHINE_ARN
};

return stepfunctions.StartExecution(params);

我得到以下错误：

响应
{
“errorType”：“TypeError”，
“errorMessage”：“stepfunctions.StartExecution不是函数”，
“跟踪”：[
“TypeError:stepfunctions.StartExecution不是函数”，
“at/var/task/index.js:119:26”，
“在包装器（/var/task/node_modules/async/dist/async.js:273:20）”中，
“在Response.next（/var/task/node_modules/async/dist/async.js:4585:24）”中，
”他回答道。
即使是这个：

该功能应该在那里可用

我错过了什么/做错了什么

谢谢！
您有一个打字错误……是小写的
s
：

startExecution
vs
startExecution

啊，我的错。到处都写着大写字母（a）。谢谢！
Response
{
  "errorType": "TypeError",
  "errorMessage": "stepfunctions.StartExecution is not a function",
  "trace": [
    "TypeError: stepfunctions.StartExecution is not a function",
    "    at /var/task/index.js:119:26",
    "    at wrapper (/var/task/node_modules/async/dist/async.js:273:20)",
    "    at Response.next (/var/task/node_modules/async/dist/async.js:4585:24)",
    "    at Response.<anonymous> (/var/task/node_modules/async/dist/async.js:326:20)",
    "    at Request.<anonymous> (/var/runtime/node_modules/aws-sdk/lib/request.js:369:18)",
    "    at Request.callListeners (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:106:20)",
    "    at Request.emit (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:78:10)",
    "    at Request.emit (/var/runtime/node_modules/aws-sdk/lib/request.js:688:14)",
    "    at Request.transition (/var/runtime/node_modules/aws-sdk/lib/request.js:22:10)",
    "    at AcceptorStateMachine.runTo (/var/runtime/node_modules/aws-sdk/lib/state_machine.js:14:12)"
  ]
}