@Nullable
  private Context getContext() {
    Callback callback = getCallback();
    if (callback == null) {
      return null;
    }

    if (callback instanceof View) {
      return ((View) callback).getContext();
    }
    return null;
  }
By default, Lottie will look in src/assets/fonts/FONT_NAME.ttf
where FONT_NAME is the fFamily specified in your Lottie file.
If your fonts have a different extension, you can override the
default here.
<p>
Alternatively, you can use {@link #setFontAssetDelegate(FontAssetDelegate)}
for more control.

@see #setFontAssetDelegate(FontAssetDelegate)
lottie/src/main/java/com/airbnb/lottie/LottieDrawable.java