how to use functions inside a sikuli script

I have been programming in C for a very long time.
As you well know, in C all of the functions are declared up front, or
can be, there are other ways also, ie prototypes....

Then in main, I can call those functions as many times as I want to.
Is there a way to do this same thing in a sikuli script ?

int functionOne()
{
  <some code>
}

int functionTwo()
{
  <some code>
}

int functionThree()
{
  <some code>
}

int main(int argc, char *argv[])
{

  functionOne();

 functionTwo();

 functionThree();

 functionTwo();

 functionOne();

} /* End main */