TypeError: _gulp2.default.series is not a function
at Object. (C:/Users/Administrator/Desktop/mtt-web/tasks/beautify.js:73:28)
at Module._compile (module.js:652:30)
at loader (C:\Users\Administrator\Desktop\mtt-web\node_modules\babel-register\lib\node.js:144:5)
at Object.require.extensions.(anonymous function) [as .js] (C:\Users\Administrator\Desktop\mtt-web\node_modules\babel-register\lib\node.js:154:7)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)
at Function.Module._load (module.js:497:3)
at Module.require (module.js:596:17)
at require (internal/module.js:11:18)
at requireDir (C:\Users\Administrator\Desktop\mtt-web\node_modules\require-dir\index.js:123:33)
at Object. (C:/Users/Administrator/Desktop/mtt-web/gulpfile.babel.js:13:1)
at Module._compile (module.js:652:30)
at loader (C:\Users\Administrator\Desktop\mtt-web\node_modules\babel-register\lib\node.js:144:5)
at Object.require.extensions.(anonymous function) [as .js] (C:\Users\Administrator\Desktop\mtt-web\node_modules\babel-register\lib\node.js:154:7)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)