Pie Grid Multi Option Error

[jason111neo]

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[X ] bug report => search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request => Please do not submit support request here

Current behavior It only allows single data

Expected behavior upon changing the data to multi, it should work, instead having toLocaleString error

Reproduction of the problem as expected

What is the motivation / use case for changing the behavior? Multiple data sets in a pie grid

Please tell us about your environment:

• ngx-charts version: x.x.x latest

• Angular version: 2.x.x latest

• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]

• Language: [all | TypeScript X.X | ES6/7 | ES5]

[marjan-georgiev]

Could this be achieved with multiple pie charts?