云函数Error: errCode: -501007 invalid parameters 啥原因？

云函数后台报错日志：

2019-11-01T03:15:08.827Z  gDate is: 2019-11-01T03:15:08.827Z

2019-11-01T03:15:08.827Z  lDate is: 2019-12-01T03:15:08.827Z

2019-11-01T03:15:08.890Z  { Error: errCode: -501007 invalid parameters | errMsg: [InvalidParameter] Check request parameter fail. Please check your request, but if the problem cannot be solved, contact us.;

at new CloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:6389:28)

at Object.returnAsCloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:6441:16)

at Object.checkError (/var/user/node_modules/wx-server-sdk/index.js:1672:23)

at Aggregate.<anonymous> (/var/user/node_modules/wx-server-sdk/index.js:1351:41)

at step (/var/user/node_modules/tslib/tslib.js:136:27)

at Object.next (/var/user/node_modules/tslib/tslib.js:117:57)

at fulfilled (/var/user/node_modules/tslib/tslib.js:107:62)

at <anonymous>

at process._tickCallback (internal/process/next_tick.js:188:7)

errCode: -501007,

errMsg: '[InvalidParameter] Check request parameter fail. Please check your request, but if the problem cannot be solved, contact us.; ' }

END RequestId: cf12d219-fc55-11e9-945a-5254007aa7a1

Report RequestId: cf12d219-fc55-11e9-945a-5254007aa7a1 Duration:69ms Memory:256MB MaxMemoryUsed:36.683594MB

云函数代码为：