ServerlessError - serverless-step-functions-offline (Either function.handler or function.image must be defined)

[nichmica7]

ServerlessError: Either function.handler or function.image must be defined. Pass the handler name (i.e. 'index.handler') as the value for function.image.command[0].

Hi, I'm trying the serverless-step-functions-offline plugin but I'm getting the above error. Any ideas how to solve it, please?