Unhandled exception:
NoSuchMethodError: The method '[]' was called on null.
Receiver: null
Tried calling: []("windows")
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:63:5)
#1 new PubspecParams.fromYaml (file:///C:/Users/diqdq/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/squirrel-0.1.0/bin/installer_windows.dart:131:52)
#2 main (file:///C:/Users/diqdq/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/squirrel-0.1.0/bin/installer_windows.dart:212:33)