Unexpected key assets ((String)) under font

fonts:
– family: OpenSans
fonts:
– asset: assets/fonts/OpenSans-Bold.ttf
weight: 700
– asset: assets/fonts/OpenSans-Regular.ttf

- family: Quicksand
  fonts:  
    - asset: assets/fonts/Quicksand-Bold.ttf
      weight: 700
    - asset: assets/fonts/Quicksand-Regular.ttf

>Solution :

The first value is default. From second you can define weight or style. Please try this

- family: Quicksand
  fonts:  
    - asset: assets/fonts/Quicksand-Regular.ttf
    - asset: assets/fonts/Quicksand-Bold.ttf
      weight: 700