我正在尝试遵循这个简单的指南https://www.polymer-project.org/3.0/docs/tools/create-element-polymer-cli
我粘贴了整个例外：
C:\dev\polymer2\sample\my-el>polymer init
'uname' is not recognized as an internal or external command,
operable program or batch file.
? Which starter template would you like to use? polymer-3-element
info: [init] Running template polymer-3-element...
? Element name my-el
? Brief description of the element test
error: [cli.main] Uncaught exception: AssertionError [ERR_ASSERTION]: Trying to copy from a source that does not exist
: C:\Users\myuser\AppData\Roaming\npm\node_modules\polymer-cli\templates\element\polymer-3.x\.gitignore
error: [cli.main] AssertionError [ERR_ASSERTION]: Trying to copy from a source that does not exist: C:\Users\myuser\
AppData\Roaming\npm\node_modules\polymer-cli\templates\element\polymer-3.x\.gitignore
at EditionInterface.exports.copy (C:\Users\myuser\AppData\Roaming\npm\node_modules\polymer-cli\node_modules\mem-fs
-editor\lib\actions\copy.js:47:3)
at EditionInterface.module.exports [as copyTpl] (C:\Users\myuser\AppData\Roaming\npm\node_modules\polymer-cli\node
_modules\mem-fs-editor\lib\actions\copy-tpl.js:10:8)
at Polymer3ElementGenerator.writing (C:\Users\myuser\AppData\Roaming\npm\node_modules\polymer-cli\lib\init\element
\element.js:124:21)
at Object.<anonymous> (C:\Users\myuser\AppData\Roaming\npm\node_modules\polymer-cli\node_modules\yeoman-generator\
lib\index.js:417:23)
at C:\Users\myuser\AppData\Roaming\npm\node_modules\polymer-cli\node_modules\run-async\index.js:25:25
at new Promise (<anonymous>)
at C:\Users\myuser\AppData\Roaming\npm\node_modules\polymer-cli\node_modules\run-async\index.js:24:19
at C:\Users\myuser\AppData\Roaming\npm\node_modules\polymer-cli\node_modules\yeoman-generator\lib\index.js:418:9
at runCallback (timers.js:794:20)
at tryOnImmediate (timers.js:752:5)