facing issue with herowebpart.ts file on onSave:

[pparupati]

(property) onSave: (filePickerResult: IFilePickerResult[]) => {
new (type: string, eventInitDict?: EventInit): Event;
prototype: Event;
readonly AT_TARGET: number;
readonly BUBBLING_PHASE: number;
readonly CAPTURING_PHASE: number;
readonly NONE: number;
}
No overload matches this call.
The last overload gave the following error.
Type '(filePickerResult: IFilePickerResult[]) => { new (type: string, eventInitDict?: EventInit): Event; prototype: Event; readonly AT_TARGET: number; readonly BUBBLING_PHASE: number; readonly CAPTURING_PHASE: number; readonly NONE: number; }' is not assignable to type '(filePickerResult: IFilePickerResult) => void'.
Types of parameters 'filePickerResult' and 'filePickerResult' are incompatible.
Type 'IFilePickerResult' is missing the following properties from type 'IFilePickerResult[]': length, pop, push, concat, and 16 more.ts(2769)