# Heudiconv heuristic: replacing characters in acq-label

Hello,

I have come across heuristics where you can modify the `{session}` label of a BIDS filename with a function at the end of the heuristic. Here is an example:

``````def ReplaceSession(sesname):
return sesname.replace("-", "x").replace("_", "x")
``````

Is there any that could modify the acq- label?

Thanks in advance, and please let me know if I can elaborate in any way.

There are a few example heuristics included within heudiconv that do just this, take a look at how this one changes the acq label based on the series name.