The following code snippet illustrates this rule:

function func1() { // Compliant
  return;
}

function func2() { // Compliant
}

function func3(); // Compliant

function func4() { // Non-compliant - there are two points of exit
  if (false) {
    return;
  }
}

function func5() { // Non-compliant - there are two points of exit
  if (a > 0) {
    return 0;
  }
  return -1;
}