Confused about handleSubmit method

These are two separate functions in two different classes, although the function in the parent container is passed into the passed into the child component. Data doesn't normally get passed from child to parent in React but the data from the component needs to get to the Redux container to change state (this gets filled out in the next stage of the course). So we pass down a function to call when a submit happens that takes the data the container wants as an argument. The component's handleSubmit() is called when the button is pressed, which in turn calls the function supplied through props by the parent.