[Closed] getExprText error

Hi. I’m trying to get the expression text from a position_wire controller. the getExprText method is probably what i want, but when i use it like this:

  -- cntl is some position_wire controller
  cntl.getExprText 1

i get an error message : Argument count error: getExprText wanted 2, got 1
what is the second argument it wants? this is what the helpfile has to say:

[left]<string>getExprText <index>index
[/left]
[left]This method returns the expression string of the i-th wire parameter.
[/left]
[left]<index>index: The index of the parameter.
[/left]