Interfaces [typescript] - Typescript to Python field guide

interfaces.ts

interface FileHandler {
  open: () => string;
  close: () => void;
}

// with usage like

function getContents(fileHandler: FileHandler): string {
  try {
    return fileHandler.open();
  } finally {
    fileHandler.close();
  }
}

const myFile = {
  open: () => "hello",
  close: () => null,
};

const contents = getContents(myFile); // "hello"