I want to calculate the SPL of an audio file that had been recorded and processed by my raspberry pi + cirrus logic audio card.

Is there anyway to go about doing this, preferably via python? I don't really know how to continue, as I had finished processing the audio file, but now I need to determine the amplitude/SPL of the file (other than viewing the frequency spectrum plot on audacity which doesn't really give an accurate/precise reading). Small Bio